Electronics Assistant

Electronics Assistant is a Windows program that performs electronics-related calculations. It includes a resistor colour code calculator, resistance, capacitance and power calculations and more. Details of calculations can be saved or printed. It provides all the functions found in the calculators section of this site and more in a stand-alone user 
friendly program.



Version 4.1 includes the following new features:

• Updated user interface
• Extra calculators for inductance and frequency
• Calculation of nearest preferred resistor values with a choice of 5 series from E12 to E192
• Links to open Windows Calculator and up to 3 user-defined programs from Electronics Assistant
• Information panels can be toggled on or off to save space when not required
• Built-in automatic new version update check
• Various bug fixes and enhancements

Version 4.1 also fixes a number of errors found in version 4.0.
Electronics Assistant (EXE File, 460 kB)

Free Circuit Design/Simulation Tools

Free OrCAD Demo program, which includes demo versions of: OrCAD Capture CIS, PSpice A/D, OrCAD Layout, and SPECCTRA for OrCAD. The limitations of this demo are in the size and complexity of the design.

OrCAD Demo

Freeware program for MAC and Windows to draw and analyze electrical circuits.

Solve Elec

Freeware open-source program for drawing circuits running on Windows. It includes drawing libraries, a SPICE template engine and can export to PCB design programs.

TinyCAD

Open-source circuit-design program for Unix/X11.

XCircuit

Free PCB Design Tools

Freeware open-source printed circuit board layout editor for Windows.
FreePCB


An interactive printed circuit board editor for Unix/X11. It includes a rats nest feature, auto-router, trace optimizer, design rule checking, and can provide RS-274-X (Gerber), NC drill, and centroid data (X-Y data) output for use in the board fabrication and assembly process.
PCB


A free schematic capture and PCB Layout program for Windows.
PCB Artist

Oscilloscope for Windows

Digital Oscilloscope Uses PC Sound Card for Input

Oscilloscope for Windows is a Windows application that converts your PC into a powerful dual-trace oscilloscope.

Oscilloscope uses your PC's sound card as an Analog-to-Digital Converter (ADC) to digitize any input waveform (speech, music, electric signal, etc.) and then presents it on the monitor in real time, allowing the user to control the display in the same way as on a conventional "standalone" scope, for example change gain, timebase or plot Lissajous patterns.

Download Digital Oscilloscope - 91 kB

Schematic Programs

Design Works Lite

One of the best schematic programs we've come across is Design Works Lite and although we have never used it extensively nor fully explored its full capabilities we have seen sufficient to be thoroughly impressed. The "Lite" version can be run unregistered.

Download Design Works Lite.

CAD126

Another little free schematic circuit drawing program recommended to me but I haven't had time to run is CAD126. It is described as an entry level ciruit design program - it's FREE and about 200K in zip file size.

Download CAD126 - 208K

ExpressPCB

This site I came across, ExpressPCB, provides FREE PCB drawing software you can download. You can print it out and do your own thing OR better yet submit the drawing electronically to have a prototype board manufactured.

As Stan from ExpressPCB explained it to me:

"There are two parts to ExpressPCB, free PC board layout software and a low costs PC board manufacturing service. The ExpressPCB CAD software runs with Windows 95, 98 or NT. Designing double-sided boards is a snap with the program's very intuitive user interface. ExpressPCB manufactures very high quality double-sided boards with plated-through holes. Their board manufacturing is both very fast and economical. Most orders are shipped the next business day and for as little as $59.
See http://www.expresspcb.com for all of the details."

Automatic time correction for your PC

SocketWatch

Another personal recommendation. I use it all the time and I paid my US$10.00 registration fee. I have no connection apart from being a very satisfied user.

Absolutely brilliant! SocketWatch is an SNTP client that gets accurate time information over the Internet. If you are connected to the Internet and want your PC clock to be as accurate as possible, SocketWatch is for you. Can be run unregistered but the registered version naturally offers superior features.

I've found over two years my PC receives a daily correction of about 9.369 seconds. Just one indication of the poor time keeping of a PC's clock. At that rate over a month my PC's time would be in error nearly five minutes! Check your time now and see how far off you are.

SocketWatch is not your father’s pocketwatch, but is as indispensable to your connected PC running Windows. In today’s wired world, keeping an accurate clock is more important than ever for the personal computer. To know how accurate is that time critical information you got from the Web, to be sure which version of that file in your Windows Briefcase is the latest, you need your computer, all the computers you use to be synchronized. The best way to do this is to synchronize your PC to the universal time signals available through the Internet.

I use it in conjunction with the Customisable Clock for Windows Task Bar above.

Download SocketWatch latest version Version 3.5b (build 146) Updated 30 Jan. 2002 - 616kB.

Linear Simulator for RF and AC Circuits

NOVA-686 - Shareware $US25.00

Written as a design aid for the RF circuit designer, radio amateur, hobbyist, and student. The primary aim of NOVA-686 was radio frequency design, however this program has proven to be excellent for all analog designs. Not intended to replace spice (the defacto standard) NOVA-686 is strong in areas where Pspice is weak, such as: fast analysis rate, optimization, tweaking, S-parameters, Monte Carlo analysis, and *accurate* RF component models.

Download NOVA-686 - 230K

Digital Simulator

Digital Works 3.04 is a graphical design tool that enables you to construct digital logic circuits and to analyse their behaviour through real time simulation. Its intuitive, easy to use interface makes it the ideal choice for learning or teaching digital electronics. You can even prototype simple digital electronic circuits before you actually build them.

You can download a free, fully functional evaluation copy of Digital Works for Windows 95, 98 and NT 4

Download Digital Works 3.04 - 1659 Kb

Micrometals RF Design Software

Micrometals FREE RF design software, RF-Toroid was written as a supplement to the Micrometals RF Application catalog. Much emphasis was put into calculating the location of the Self resonate frequencies for series and shunt inductors. RF-Toroid is for use DC to 300 MHz. Much research went in to the calculation and corrections from the standard formulas for low perm & phenolic cores to better predict the RF style of winding and application. Some features include SRF for series and shunt cores, peak Q curve ranges and 200 & 360 degree coverage to achieve the best product possible for the microwave designer who needs accurate and abundant information at the finger tips to compare one core to another simultaneously. The custom core feature allows for custom shaped cores, stacking cores side by side , ferrite cores and machining custom phenolic cores from plastic, wood, ect... Micrometals hope this tool will serve you well.

Download Micrometals RF Design Software - 397 Kb

Motorola Impedance Matching Program - FREE

Motorola's Impedance Matching Program is a specialized form of CAD specifically developed for RF power amplifier circuit design. It provides a simple environment for entering and analyzing impedance matching circuitry regularly employed in RF Power amplifier design.

Data sheets for RF devices contain large signal impedances (measured at a single combination of frequency, voltage, power level and power dissipation). These impedances must generally be transformed to another set of impedances (50 W or the input/output impedance of another device). To do this, MIMP provides a standard library of passive circuit elements; including various combinations of capacitors, inductors and transmission lines in both series and shunt configurations. It also contains a unique, DISTRIBUTED CAPACITANCE ELEMENT that models a capacitor distributed along a transmission line.

http://e-www.motorola.com/rf/designtds/mimp.html - 119K

LTspice/SwitcherCAD™ III

Fully functional Spice III simulator from Linear Technology

TLTC SwitcherCAD™ III is a fully functional Spice III simulator with enhancements and models for easing the simulation of switching regulators. This Spice is a high performance circuit simulator, integrated waveform viewer, which also includes schematic capture. Our enhancements to Spice have made simulating switching regulators extremely fast compared to normal Spice simulators.

Included in this download are Spice, Macro Models for 80% of Linear Technology's switching regulators and over 200 op amp models. Furthermore, resistors, transistors and MOSFET models are included as part of this package. With this Spice simulation, viewing of the waveforms of most switching regulators can be achieved in a few minutes on a high performance PC. Also, full circuits using op amps or transistors can easily be simulated.

Download LTspice/SwitcherCAD™ III:

LTspice/SwitcherCAD™ III 4 mB

CircuitMaker Student Version

This edition of CircuitMaker was created especially to provide students with access to one of the best resources available for learning electronics.

The CircuitMaker Student Version is the same as CircuitMaker Version 6, with the following limitations:

• Maximum of 50 devices per design (any type);
• Device library limited to 1,000 models;
• Symbol editor and Macro feature disabled;
• PCB netlist export limited to TraxMaker format;
• Technical support limited to fax and email only.

Download the CircuitMaker Student Version:

The CircuitMaker Student Version is available for download via http or ftp transfer