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Introduction

Electric Circuit Studio (ECStudio) is a set of tools used for building electronic circuits, SPICE simulation, and calculation of circuits. These tools are complemented by the information center containing resources, connector pinouts and interactive book explaining basic electrical theorems, laws and circuits. It is a useful application for all electronics hobbyists, students, or other people with an interest in electronics.

Schematic editor and SPICE simulator allow easy creation of circuit diagrams and SPICE analysis of the created circuits. ECStudio simulator is focused on visual representation of simulated results, such that simulated voltages and currents can be placed elsewhere in the circuit, as a text or graph. Moreover, the magnitude and polarity of voltages and currents can be represented by visual indicators, so you can check the results quickly. All results can be additionally displayed on the top plot, where they can be explored using two cursors.

DC, AC and Transient analyses are supported. The simulation can be run repeatedly (in Transient analysis) and results can be displayed consecutively with a user controlled speed (in all analysis types), or all simulation results are displayed immediately. When the results are shown consecutively, you can control parameters of circuit elements by the seek bar and see the change of results in real time.

The application supports two modes: Normal and Restricted. The Restricted mode differs from the Normal mode in that the size of the drawing canvas is restricted to the size of the circuit, elements cannot be inserted, moved, rotated, flipped or deleted, and the undo, redo, saving and opening circuits are not allowed. This mode is intended to be used only for simulation of circuits.

The application uses the shared storage to store circuits, pictures, models, screenshots, exported and log files. This storage is usually internal memory, or it can be an external SD card. The location of the application directory is Documents/ECStudio (or Documents/ElectricCircuitStudio for the free version of the application).

Important notes:
The app internally uses industry standard SPICE program of version 3. If you will encounter any issue with the simulation, you can try to do steps valid for this SPICE program explained for example in the Lessons in Electric Circuits: Volume V - Reference book, page 81.
To resolve the "Timestep too small" issue in Transient analysis, you can try these steps:
- Decrease the timestep (Stop - Start) and/or increase the value of Points in Circuit Properties.
- Uncheck "Use initial conditions" in Circuit Properties.
- Increase "Absolute tolerance" in App Settings.
- Increase Output capacitances of flip-flops, if any.
- Increase Rise and Fall times of pulsed sources (Vpulse), if any.
- Send us your circuit (to info@ecstudiosystems.com) and we will correct it.

User Interface

Basic user interface of the application consists of the Action bar, Toolbar, Element bar, Plot window, Menu, and Drawing canvas. The Menu can be opened by taping the Overflow icon:

interface

Toolbar Buttons

Properties button Properties
Eye button Quick Show V or I
Play button Run/Stop
Delete command Delete
Rotate command Rotate Clockwise
Flip command Flip Horizontally
Undo command Undo
Redo command Redo
Bring to Front command Bring to Front
Send to Back command Send to Back
Cut command Cut
Copy command Copy
Paste command Paste
Select Select
Select all Select All
Reset view Reset View
Screenshot command Screenshot
Previous page Previous Page
Next page Next Page

Modifying User Interface

To modify the user interface, you can use the following commands.

Reset View

To scale the Drawing canvas to fit the whole circuit, tap the Reset View button from the Toolbar.

Zoom View

The Drawing canvas can be reduced or enlarged with a double-tap (if applicable) or a two-finger spread gesture.

Restricted Mode

If the Restricted Mode item from the Menu is checked, the view will be scaled to fit the whole circuit and the application will be switched to the Restricted mode.

Sim. Shows Plot

If the Sim. Shows Plot item from the Menu is checked, the Plot window will be displayed after the start of simulation. This window can be hid immediately by a fling gesture.

Show Bottom Bar

If the Show Bottom Bar item from the Menu is checked, the Element bar will be shown on the bottom.

Circuit Management

Circuits used in ECStudio are located in the directory <app directory>/Circuits.

Creating New Circuits

Choose New Circuit from the Menu. This opens an empty document in the Normal mode.

Saving Circuits

Use Save from the Menu to save the current circuit.

Use Save As from the Menu to save the current circuit with a different file name.

Opening Circuits

Use Open Circuit from the Menu to show Open Circuit dialog, allowing you to find a desired file and tap on its name. Or you can use Favorites to open a bookmark file. In the Open Circuit dialog you can delete, rename or bookmark (add to favorites) a file using the long tap gesture. There is also a search form to quickly search for a file.

Properties of Circuits

Choose Circuit Properties from the Menu to show Circuit Properties dialog, allowing you to change various settings of the current circuit.

Title

Enter a single-line title text.

Description

Enter a description text. This text is visible in Open Circuit dialog.

TRANSIENT ANALYSIS

Start
Start time for the Transient analysis.

Stop
Stop time for the Transient analysis.

Points
The number of points for the Transient analysis. It can be from 20 to 5000.

Use initial conditions
If checked, the simulator uses the initial values of appropriate elements entered using an extra parameter (IC=...) as the initial conditions in the Transient analysis.

Automatic times
If checked and the circuit contains Vsin and/or Vpulse sources, the start and stop times are calculated automatically from the periods of these sources.

DC ANALYSIS

Start
Start voltage for the DC analysis.

Stop
Stop voltage for the DC analysis.

Step
Step voltage for the DC analysis.

Source
Select a name of the independent voltage source to be swept.

AC ANALYSIS

Start
Start frequency for the AC analysis.

Stop
Stop frequency for the AC analysis.

Points
The number of points for the AC analysis. It can be from 1 to 10000.

Type
Select a type of the x-axis. The LIN type makes the x-axis to be divided linearly. The DEC and OCT makes the x-axis to be divided logarithmically (by decades or octaves).

Analysis

Select a type of the analysis for the simulation. The most common analysis is the Transient analysis, which calculates (instantaneous) voltages and currents of the circuit as a function of time.

In the AC analysis, the frequency of sinusoidal voltage sources (Vsin) is swept over a user-specified range. The magnitude, real value, imaginary value and phase of (small-signal) voltages and currents are then calculated as a function of frequency. It follows that at least one sinusoidal voltage source is required for a meaningful AC analysis. Further, only Amplitude and Phase parameters of this source are used in the AC analysis.

In the DC analysis, a chosen DC voltage source is swept from the Start voltage to the Stop voltage in increments of the Step voltage. DC voltages and currents of the circuit are then calculated for each value of the sweep. It follows that at least one DC voltage source is required in the DC analysis.

Note:
In the DC and Transient analysis, only Real (instantaneous) number types can be used.

Show grid

Adds gridlines to the X and Y axes of the circuit.

Grid color

Displays Select color dialog to set the color of gridlines.

Show pin numbers

Shows pin numbers of selected elements.

Canvas text color

Displays Select color dialog to set the color of pin numbers and label texts of newly created elements.

Canvas background color

Displays Select color dialog to set the color of Drawing Canvas.

Plot foreground color

Sets the color of Plot window.

Plot background color

Sets the color of texts and lines of the Plot window.

Box border color

Sets the color of label border.

Controls color

Displays Select color dialog to set the color of various control elements (scrollbars, cursor lines, etc.).

Symbol line width

Sets the width of element's lines. It can be between 0.2 and 20.

Symbol line color

Sets the color of element's lines and circuit junctions.

Graph line width

Sets the width of graph lines. It can be between 1 and 10.

Minimum size of indicators

Sets the minimum relative size of current and voltage indicators. It can be between 0 and 1.

Maximum size of indicators

Sets the maximum absolute size of current (width) and voltage (radius) indicators in pixels. It can be between 1 and 100.

Box margins

Sets margins of all labels except Output labels.

Textbox margins

Sets margins of all Textbox elements.

IEC-style symbols

Displays IEC-style symbols.

Precision

Controls the precision of numerical results in the Output labels as well as in the Plot window. It can be from 2 to 10. The precision of results in the Plot window will be Precision + 1.

Reset properties (white or black theme)

Resets properties of the current circuit to the default values, except for Title and Description.

Elements

Each element can have attached several labels:

Element

These labels are used to display simulation results, parameters of elements, or some text. When you move an element, its labels also move, but labels can be moved or rotated independently of elements. By rotating or flipping an element you can reset the position and rotation of the element's labels.

Note:
If a file with the name library is copied to the ECStudio directory, the file will be used instead of the internal file to load element definitions. This can be used for eventual change of properties of elements and labels, but only by experienced users!

Labels

Labels can be of four types: Parameter labels, Text labels, Output labels, and Designation labels. Parameter labels are used to control the main parameter of elements. Text labels can be used only for showing a text. Output labels allow to display plots, indicators, graphs and numerical values of corresponding variables (voltages or currents). And finally, designation labels are used to mark elements.

Output labels

An Output label is always attached to a variable of the circuit. This variable can be a voltage, voltage drop or current. In the case of the voltage or current, the Output label belongs to one pin of the element and one node of the circuit. As the voltage drop is always determined between two points of the circuit, the Output label attached to a voltage drop belongs to two pins of the element and two nodes of the circuit.

The numerical value and graph of a variable attached to the Output label are displayed inside the label. The graph of a variable can be shown also in the Plot window, while a graphical representation (indicator) of the numerical value can be drawn in the element. The type of the variable, pin and node numbers pertaining to the Output label are shown in the top line of the Label Properties Dialog. Before simulation, Output labels contain a text, which show a type of the variable (volt. for voltage or voltage drop and curr. for current) and the pin numbers, for which the labels will display the variable values or graphs.

In the case of the voltage drop variable, the label belonging to this variable will display the voltage drop (difference) between two pins of the element. The numerical value displayed in the label is an absolute value, as the direction (sign) of the voltage is shown by an appropriate indicator:

Voltage drop

In the case of the voltage variable, the label belonging to this variable will display the voltage between the pin of the element and the ground:

Voltage

And in the case of the current variable, the label will display the current flowing to the pin of the element. The numerical value displayed in the label is an absolute value, as the current direction (sign) is shown by an appropriate indicator:

Current

Indicators

Indicators are used for visual representation of simulated results. They are of three types: current indicators, voltage indicators, and voltage drop indicators.

Current indicator

Current indicators are drawn as colored arrows inside elements, which show the direction of the current through elements (in the Transient and DC analyses) or the sign of current (in the AC analysis). The width of arrows represents a relative magnitude of the current.

Voltage indicator

Voltage indicators are drawn as colored circles around the appropriate pin. The radius of a circle represents a relative magnitude of the voltage.

Voltage drop indicator

Voltage drop indicators are drawn as colored line arrows between appropriate pins. The length of an arrow represents a relative magnitude of the voltage drop. The line arrow also shows the direction of the voltage drop in the Transient and DC analyses, or the sign of drop in the AC analysis (see the example below).

AC example

The picture above shows imaginary values of voltages across three elements in a simple circuit. As the voltage across the capacitor C3 points from pin 2 to pin 1 (blue arrow), which is the opposite direction comparing to its default direction, the value of this voltage is considered as negative. This corresponds to the negative value displayed on the top Plot window.

Note:
The phase type of a variable (no matter it is current or voltage) in the AC analysis is considered as a separated type of the variable for the purpose of calculation of relative magnitude. The relative magnitude of a variable is the ratio of the absolute value of the variable to the maximum absolute value of all active variables of the same type (current, voltage or phase). This maximum value is calculated through the whole simulation interval.

Note:
An Output label is active, if it has at least one of these options checked in the Label Properties Dialog: Show value, Show graph, Show indicator, Show plot. The variable belonging to the active label is also considered as active.

Inserting Elements

The Element bar on the bottom of screen allows inserting these elements:

Wire Wire

Ground Ground (Gnd)

Resistor Resistor
ParameterDescription
ResistanceResistance in Ohms

Capacitor Capacitor
ParameterDescription
CapacitanceCapacitance in Farads
Extra The Extra parameter (IC=<volts>V) sets the initial (time = 0) value of capacitor voltage. Note that the initial conditions apply only if the Use initial conditions is checked on the Circuit Properties dialog.

Polarized capacitor Polarized capacitor
ParameterDescription
CapacitanceCapacitance in Farads
Extra The Extra parameter (IC=<volts>V) sets the initial (time = 0) value of capacitor voltage. Note that the initial conditions apply only if the Use initial conditions is checked on the Circuit Properties dialog.

Inductor Inductor
ParameterDescription
InductanceInductance in Henries
Extra The Extra parameter (IC=<amps>A) sets the initial (time = 0) value of inductor current that flows from pin 1, through the inductor, to pin 2. Note that the initial conditions apply only if the Use initial conditions is checked on the Circuit Properties dialog.

VDC DC voltage source
ParameterDescription
VoltageDC voltage of the source in the DC and Transient analyses. In the AC analysis, this source is a short circuit.

Vpulse Pulse voltage source (Vpulse)
A voltage source usable in the Transient analysis. In the AC and DC analyses, this source is a short circuit. A single pulse of this source is described by the following table:
TimeValue
0Initial
DelayInitial
Delay + RisePulsed
Delay + Rise + WidthPulsed
Delay + Rise + Width + FallInitial
Period + DelayInitial

Vsin Sinusoidal voltage source (Vsin)
In the AC analysis, only Amplitude and Phase parameters of this source are used. In the Transient analysis, all parameters are used, and the Phase then represents the delay of the voltage.

IDC DC current source
ParameterDescription
CurrentDC current of the source in the DC and Transient analyses. In the AC analysis, this source is an open circuit.

Text Single-line text (Textbox)

Picture Picture

Diode Diode
For description of the diode's main parameters (Saturation current, Ohmic-series resistance, Emission coefficient, Transit time, Junction capacitance), see here.
ParameterDescription
Extra The Extra parameter (IC=<volts>) sets the initial voltage of the diode. Note that the initial conditions apply only if the Use initial conditions is checked on the Circuit Properties dialog.
Model The filename of the diode model. See here.

Zener diode Zener diode
For description of the diode's main parameters (Breakdown voltage, Saturation current, Ohmic-series resistance, Emission coefficient, Transit time, Junction capacitance), see here.
ParameterDescription
Extra The Extra parameter (IC=<volts>) sets the initial voltage of the diode. Note that the initial conditions apply only if the Use initial conditions is checked on the Circuit Properties dialog.
Model The filename of the diode model. See here.

LED diode LED diode
For description of the diode's main parameters (Saturation current, Ohmic-series resistance, Emission coefficient, Transit time, Junction capacitance), see here.
ParameterDescription
Extra The Extra parameter (IC=<volts>) sets the initial voltage of the diode. Note that the initial conditions apply only if the Use initial conditions is checked on the Circuit Properties dialog.
Model The filename of the diode model. See here.

NPN transistor NPN transistor
For description of the transistors's main parameters (Saturation current, Forward beta, Reverse beta, Forward transit time, Reverse transit time, Base resistance, Emitter resistance, Collector resistance), see Wikipedia.
ParameterDescription
Extra The Extra parameter (IC=<VBE>, <VCE>) sets the initial voltages (VBE and VCE) of the transistor. Note that the initial conditions apply only if the Use initial conditions is checked on the Circuit Properties dialog.
Model The filename of the transistor model. See here.

PNP transistor PNP transistor
For description of the transistors's main parameters (Saturation current, Forward beta, Reverse beta, Forward transit time, Reverse transit time, Base resistance, Emitter resistance, Collector resistance), see Wikipedia.
ParameterDescription
Extra The Extra parameter (IC=<VBE>, <VCE>) sets the initial voltages (VBE and VCE) of the transistor. Note that the initial conditions apply only if the Use initial conditions is checked on the Circuit Properties dialog.
Model The filename of the transistor model. See here.

NMOS transistor NMOS transistor
ParameterDescription
Treshold voltage Zero-bias threshold voltage (VTO). VTO is positive for enhancement mode and negative for depletion mode N-channel MOS transistors. See Wikipedia.
Transconductance Transconductance parameter (KP).
Lambda Channel-length modulation. See Wikipedia.
Extra The Extra parameter (IC=<VDS>, <VGS>, <VBS>) sets the initial voltages (VDS, VGS and VBS) of the transistor. Note that the initial conditions apply only if the Use initial conditions is checked on the Circuit Properties dialog.
Model The filename of the transistor model. See here.

PMOS transistor PMOS transistor
ParameterDescription
Treshold voltage Zero-bias threshold voltage (VTO). VTO is negative for enhancement mode and positive for depletion mode P-channel MOS transistors. See Wikipedia.
Transconductance Transconductance parameter (KP).
Lambda Channel-length modulation. See Wikipedia.
Extra The Extra parameter (IC=<VDS>, <VGS>, <VBS>) sets the initial voltages (VDS, VGS and VBS) of the transistor. Note that the initial conditions apply only if the Use initial conditions is checked on the Circuit Properties dialog.
Model The filename of the transistor model. See here.

NJFET transistor NJFET transistor
ParameterDescription
Treshold voltage Threshold voltage (VTO), see Wikipedia.
Transconductance Transconductance parameter (BETA).
Channel-length modulation Channel-length modulation (LAMBDA), determines the output conductance. See Wikipedia.
Drain resistance Drain ohmic resistance
Source resistance Source ohmic resistance
Extra The Extra parameter (IC=<VDS>, <VGS>) sets the initial voltages (VDS and VGS) of the transistor. Note that the initial conditions apply only if the Use initial conditions is checked on the Circuit Properties dialog.
Model The filename of the transistor model. See here.

PJFET transistor PJFET transistor
ParameterDescription
Treshold voltage Threshold voltage (VTO), see Wikipedia.
Transconductance Transconductance parameter (BETA).
Channel-length modulation Channel-length modulation (LAMBDA), determines the output conductance. See Wikipedia.
Drain resistance Drain ohmic resistance
Source resistance Source ohmic resistance
Extra The Extra parameter (IC=<VDS>, <VGS>) sets the initial voltages (VDS and VGS) of the transistor. Note that the initial conditions apply only if the Use initial conditions is checked on the Circuit Properties dialog.
Model The filename of the transistor model. See here.

NOT logic gate NOT logic gate
ParameterDescription
VCC Power supply voltage
Threshold voltage Threshold voltage of the gate's input
Output capacitance Parallel capacitance placed at the gate's output

AND logic gate AND logic gate
ParameterDescription
VCC Power supply voltage
Threshold voltage Threshold voltage of both inputs of the gate
Output capacitance Parallel capacitance placed at the gate's output

NAND logic gate NAND logic gate
ParameterDescription
VCC Power supply voltage
Threshold voltage Threshold voltage of both inputs of the gate
Output capacitance Parallel capacitance placed at the gate's output

OR logic gate OR logic gate
ParameterDescription
VCC Power supply voltage
Threshold voltage Threshold voltage of both inputs of the gate
Output capacitance Parallel capacitance placed at the gate's output

NOR logic gate NOR logic gate
ParameterDescription
VCC Power supply voltage
Threshold voltage Threshold voltage of both inputs of the gate
Output capacitance Parallel capacitance placed at the gate's output

XOR logic gate XOR logic gate
ParameterDescription
VCC Power supply voltage
Threshold voltage Threshold voltage of both inputs of the gate
Output capacitance Parallel capacitance placed at the gate's output

XNOR logic gate XNOR logic gate
ParameterDescription
VCC Power supply voltage
Threshold voltage Threshold voltage of both inputs of the gate
Output capacitance Parallel capacitance placed at the gate's output

SR latch SR latch
ParameterDescription
VCC Power supply voltage
Threshold voltage Threshold voltage of both inputs of the latch
Output capacitance Parallel capacitance placed at the latch's Q output
Inverted output capacitance Parallel capacitance placed at the latch's inverted output

D flip-flop D flip-flop
ParameterDescription
VCC Power supply voltage
Threshold voltage Threshold voltage of both inputs of the flip-flop
Output capacitance Parallel capacitance placed at the flip-flop's Q output
Inverted output capacitance Parallel capacitance placed at the flip-flop's inverted output

T flip-flop T flip-flop
ParameterDescription
VCC Power supply voltage
Threshold voltage Threshold voltage of both inputs of the flip-flop
Output capacitance Parallel capacitance placed at the flip-flop's Q output
Inverted output capacitance Parallel capacitance placed at the flip-flop's inverted output

JK flip-flop JK flip-flop
ParameterDescription
VCC Power supply voltage
Threshold voltage Threshold voltage of all inputs of the flip-flop
Output capacitance Parallel capacitance placed at the flip-flop's Q output
Inverted output capacitance Parallel capacitance placed at the flip-flop's inverted output

Operational amplifier Operational amplifier
ParameterDescription
Gain Differential voltage gain
Input resistance The value of resistance placed between two inputs of the Operation amplifier.

555 timer 555 timer

LM317 LM317

LM337 LM337

7805 7805

7905 7905

VCVS Voltage controlled voltage source (VCVS)
ParameterDescription
Gain Voltage gain

VCCS Voltage controlled current source (VCCS)
ParameterDescription
Transconductance Transconductance

CCVS Current controlled voltage source (CCVS)
ParameterDescription
Transresistance Transresistance

CCCS Current controlled current source (CCCS)
ParameterDescription
Gain Current gain

Potentiometer 1 Potentiometer 1
ParameterDescription
Resistance Resistance between end pins of the potentiometer
Wiper position Relative position of the middle pin

Potentiometer 2 Potentiometer 2
ParameterDescription
Resistance Resistance between end pins of the potentiometer
Wiper position Relative position of the middle pin

Transformer Transformer
ParameterDescription
Coupling Coupling coefficient, see Wikipedia.
Primary inductance Inductance of the primary winding
Secondary inductance Inductance of the secondary winding

Switch SPST Switch SPST

Switch SPDT Switch SPDT

Open push-button Open push-button

Closed push-button Closed push-button

Relay SPST Relay SPST
ParameterDescription
Threshold voltage Threshold voltage of the control coil
Hysteresis voltage Hysteresis voltage of the control coil
On resistance Resistance between closed contacts
Off resistance Resistance between open contacts
Coil resistance Resistance of the control coil
Coil inductance Inductance of the control coil

Relay SPDT Relay SPDT
ParameterDescription
Threshold voltage Threshold voltage of the control coil
Hysteresis voltage Hysteresis voltage of the control coil
On resistance 1 Resistance between closed first pair of contacts
Off resistance 1 Resistance between open first pair of contacts
On resistance 2 Resistance between closed second pair of contacts
Off resistance 2 Resistance between open second pair of contacts
Coil resistance Resistance of the control coil
Coil inductance Inductance of the control coil

Crossover Crossover
ParameterDescription
Resistance Resistance between pins of the element

Crossover 2 Crossover 2
ParameterDescription
Resistance Resistance between pins of the element

Speaker Speaker
The model of Speaker consists of five elements. Two elements (Series resistance and Series inductance) are in series. These two elements are then in series with the remaining elements (Parallel resistance, Parallel inductance and Parallel capacitance), which are connected in parallel.

DC motor DC motor
The motor model is inspired by the model from ecircuitcenter.com.

Elements are inserted into the grid with a cell size of 100x100 pixels. The picture element allows inserting a bitmap picture, which should be placed in the <app directory>/Pictures directory. The name of this bitmap can be inserted through the File parameter of the element. The center of the bitmap is always positioned at a intersection of gridlines.

Models of transistors and diodes can be inserted as files into the directory <app directory>/Models. To assign a model to an element, enter the name of the model file to the Model parameter of the element. The values of numerical parameters entered through the Element Properties Menu will then be ignored. The model's name must be the same as the name of the model file.

Example models:
1N4004 - standard rectifier diode
1N4148 - small signal diode
2N2222 - general purpose NPN transistor
BC547A - general purpose NPN transistor
2N2907 - general purpose PNP transistor
J111 - N-channel JFET switch
IRF530 - power N-channel MOSFET

Note:
By a long tap on an element button you can display the name of the element.

Drawing Wires

To draw a wire, tap the Wire button in the Element bar and then tap the start and end points of the wire to be drawn. If these points do not lie on a vertical or horizontal line, the wire will be drawn using autorouting, otherwise a simple one-line wire will be created.

Selecting Elements

Select Element

To select only one element, tap some place on the element outside of the element's labels. All labels attached to the element are then displayed, and a Selection rectangle will be drawn around the element. If the "Rectangle selection" is not checked in the Menu->App Settings, the selected element will be instead painted by a Selection color.
To select multiple elements, tap the Select button in the Toolbar and then tap the top left-hand as well as bottom right-hand corners of the area containing the elements to be selected.

Deselect Element

To deselect only one element, tap some place on the element outside of the element's labels.
To deselect multiple elements, tap the Select button in the Toolbar and then double tap some place outside the circuit elements.

Select All Elements

To select all circuit elements, tap the Select All button in the Toolbar.

Select Label

To select a label, tap the element to which the label is attached and then tap the label. A red rectangle will be drawn around the label.

Moving Elements and Labels

Moving Elements

To move selected elements, tap and drag them to a new position. Elements are snapped to the grid.

Moving Labels

To move the selected label, long tap and drag it to a new position. Labels can be moved to any place of the Drawing canvas.

Editing Elements

Properties Button

The multipurpose Properties button in the Toolbar allows users to set properties of elements, labels or simulation. If there is no selected element, it shows the seek bar used to control the speed of displaying of simulation results in the Continuous mode of simulation. If a label is selected, it displays the Label Properties Dialog allowing to set properties of the label. If only one element is selected and none of its labels are marked, it displays the Element Properties Menu allowing to set parameters of the element.

Element Properties Menu

Element properties

The first line of the menu is always the name of the element. Next lines represent the properties of the element. By taping on some of these lines (if there is any) you can display a parameter window with a seek bar and two spinners allowing to set the chosen parameter:

Parameter window

The seek bar has increment of 1 and is used especially for quick changes of parameters. The left-hand spinner can be used to change the sign of the parameter, while the right-hand spinner is used for selecting a unit of the parameter. By taping the name of the parameter you can set the parameter's value through a text dialog.

Note:
For textual parameters (e.g. Model filenames), the seek bar and spinners are purposefully hidden.

Label Properties Dialog

Show text (value)
Displays the text/value in the label. In the case of an Output Label, this option can be automatically reverted, depending on the "Graph/number switching" option in the App Settings.

Show box
Displays the box in the label.

Show graph
Displays the graph in the label instead of the box and text. This option is shown only in the case of an Output Label and can be automatically reverted, depending on the "Graph/number switching" option in the App Settings.

Show indicator
Draws the indicator in the element. This option is shown only in the case of an Output Label.

Show plot
Draws the graph in the plot window. This option is shown only in the case of an Output Label.

Cursors 1
If checked, after finishing a Common mode simulation the seek bar of the first cursor will be opened below the plot window. The cursor can be used to obtain x and y values of the corresponding graph. This option is shown only in the case of an Output Label.

Cursors 2
If checked, after finishing a Common mode simulation the seek bar of the second cursor will be opened below the plot window. The cursor can be used to obtain x and y values of the corresponding graph. This option is shown only in the case of an Output Label.

Number type
Select the type of corresponding current or voltage variable. In the AC analysis, you can display the magnitude, real value, imaginary value and phase of voltages and currents. In the DC and Transient analysis, only real (instantaneous) values can be displayed. This option is shown only in the case of an Output Label.

Scale
Enter a scale of the label.

Rotation
Select a rotation of the label.

Alignment
Select an alignment of the text inside the label.

Designation
Enter a designation of the element. This item will be shown only in the case of a Designation label.

Value
Enter a value of the label. This item will be shown only in the case of a Parameter label.

Text
Enter a text of the label. This item will be shown only for text elements.

Background color
Choose a color of the label's box.

Foreground color
Choose a color of the label's text. In the case of an Output label, this item is not shown as the foreground color is chosen automatically. The same color will be used in the graph as well as Plot window.

Rounded box
If checked, the label's box will be drawn rounded.

Font
Select a font type of the label's text.

Toolbar Commands

The next commands from the Toolbar can be applied to one or more selected elements.

Cut

Copies the selected elements to the clipboard and removes them from the current circuit.

Copy

Copies the selected elements to the clipboard.

Paste

Inserts the contents of the clipboard at the location of the cut elements.

Delete

Removes the selected elements from the current circuit.

Bring to Front

Select the elements you want to bring to front, and then tap the Bring to Front button.

Send to Back

Select the elements you want to send to back, and then tap the Send to Back button.

Rotate Clockwise

You can rotate all elements along with the labels, except for wires. Select the elements you want to rotate, and then tap the Rotate Clockwise button. Labels are also rotated, according to the definition in the internal library file.

Flip Horizontally

You can flip all elements along with the labels, except for wires. Select the elements you want to flip, and then tap the Flip Horizontally button. Labels are also flipped, according to the definition in the internal library file.

The next commands from the Menu->Tools can be applied only to all circuit elements.

Show Names

Shows the designations of the current circuit elements.

Hide Names

Hides the designations of the current circuit elements.

Show Values

Shows the values of the current circuit elements.

Hide Values

Hides the values of the current circuit elements.

Quick Show Button

Quick Show (EYE) button from the Toolbar can be used to quickly show some voltages and currents of the circuit. If only one 2-pin element is selected, it toggles displaying the indicator, value and plot of the element's current. If a wire is selected, it toggles displaying the plot and value of the wire's voltage. In other cases, it toggles displaying current indicators of wires.

Notes:
If the "Graph/number switching" is checked in the Menu->App Settings, the displayed value can switch to the graph in the Transient analysis, when the value is not a constant in time. If the "Highlight wires" is checked in the Menu->App Settings and the voltage of a wire is set to show, the wire will be painted by the plot color.

Switching Switches

The switches (Switch SPST, Switch SPDT, Open push-button and Closed push-button) can be switched by long tapping the switch.

Undo and Redo

Undo

Reverses the last editing command or the last change of a property.

Redo

Reverses the action of the last Undo command.

Simulation

Running Simulation

Tap Run/Stop button in the Toolbar. This opens the menu of two items. The item Run starts the Continuous mode of simulation of a type chosen in the Properties dialog, when the results are displayed consecutively with a user controlled speed. In the case of DC and AC analyses, the simulation will stop after displaying of the last result. In the case of Transient analysis, the simulation is run repeatedly with a gradually increasing Start time of the simulation.

The item Run and Show All starts the Common mode of simulation of a type chosen in the Properties dialog. After finishing the simulation all results are displayed immediately.

When a simulation is running, it can be stopped by taping on the Run/Stop button. In the Continuous mode, the displaying of results is then paused and these results can be thereafter explored. The next tap of the Run or Run and Show All item starts a new simulation.

Note:
At least one Gnd element is required to achieve a successful simulation.

Export and Screenshots

Exporting Circuits

Use Export item from the Menu to open Export dialog.

Max. scaling factor

Down-size the image to a lower resolution. The size of target images depends on the available memory.

Quality

Enter the quality level for JPEG compression.

File name

Enter a file name for the image.

Export

Exports the circuit and places it to the ECStudio directory.

Screenshot

Taping the Screenshot button takes a screenshot without applying any theme of the device and places it to the ECStudio directory.

App Settings

Choose App Settings from the Menu to show the dialog allowing you to change various settings of the application.

Graph/number switching

If checked, Output labels will be switched between showing graph or value (number) in the Transient analysis. Then, if an Output label will be showing horizontal line for some time, the label will start to show the value.

Highlight wires

If checked, all wires set to show the voltage will be painted by the plot color.

Wire indicator color

The color of indicators of wire current shown by the Quick Show (EYE) button.

Non-transparent graphs

If checked, the transparency of all circuit graphs will be removed (i.e. alpha channel of the graph background color will be set to 255). The other components (red, green, blue) of the graph background color will be the same as components of the Canvas background color.

Theme

Theme of the newly created circuits.

Rectangle selection

If checked, selected elements will be highlighted by the rectangle. In the opposite case, they will be painted with the Selection color.

Selection color

Sets the color of selected elements and the selection rectangle.

LED effects

If checked and the LED diodes are set to show the current, the diodes will be glowing.

Absolute tolerance

Increasing this value from the default (1E-12) can help to resolve SPICE convergence problems. It is the abstol SPICE option.

Reset EEA Consent

When tapped, European users can set the EEA consent after restarting the application.

Interactive Book

Taping the Book item from the Menu displays the interactive physics book in the Restricted mode. The book contains these chapters:

1. Electric circuit
2. Nodes
3. Node voltage
4. Voltage drop
5. Electric current
6. DC current
7. AC current
8. Kirchhoff's current law
9. Kirchhoff's voltage law
10. Voltage source
11. Sine and pulse generators
12. Current source
13. Resistor
14. Ohm's law
15. Resistors in series
16. Resistors in parallel
17. Voltage divider
18. Current divider
19. Capacitor
20. Inductor

Calc & Info

Calc & Info

Taping the Calc & Info button in the Action bar displays the calculator and information center.

Calculators

The tool contains calculations of all basic circuits, laws as well as various converters. Some electrical circuits can be opened after the calculation by the simulator (with default element's parameters) to check and explore the results. The calculators are supplemented by formulas. These calculators are available:

Ohm's law
Resistors in series/parallel
Series-parallel circuit
Y-Delta transformation
Resistor for voltage attenuation
Power calculator
Voltage divider
Current divider
RLC reactance/impedance
LC resonance
Passive filters
Capacitor charging
Transformer calculations
Resistor for LED
Zener diode
Operational amplifier
LM317 voltage regulator
555 timer
A/D and D/A converters
Coil inductance
Voltage drop
Resistor color code
SMD resistor code
Inductor color code
RMS calculator
Frequency/period converter
Battery capacity conversion
Battery life
Decibel converter
PCB trace width calculator

Connectors

The pinouts of these connectors/devices are available:

SCART
VGA
DVI
HDMI
Firewire
USB
Thunderbolt
Apple Lightning
Apple dock
RS-232
Sata, eSata
PS/2
ATX power connectors
SD cards
SIM cards
Ethernet RJ45
RJ11, RJ14, RJ25
ISO10487 for car audio
XLR
LED
Raspberry GPIO

Resources

These topics are included:

Wire size
Wire insulation colors
Ampacity
Resistivity
Resistor values
Capacitor codes
Capacitor values
SMD packages
Units of measurement
SI prefixes
7400 series of integrated circuits
Voltage regulators
Logic gates
Electrical symbols
USB specifications