Circuits explained

This topic is about circuits, how they are designed, which trade offs were made and how calculations were performed. Don't expect too much university level material here. Mostly it will be rule of thumb mathematics and analyses. Plus 'guts'.

Below is a list of topics. Each 'section' contains a series of (more or less) related topics. Browse this list, using your browser's Ctrl-F search function.

Section 1: Okapi and Parilux parts

This section covers some parts of the Okapi 3 AVR ICSP programmer for the parallel printer port. It's a rather clever circuit with lots of goodies en as little 'chance elements' as possible.

  1. Power supply design
  2. Opto coupler turning on an IRF 540
  3. Dimensioning an LED
  4. Control an opto coupler from a digital I/O port
  5. Forcing a signal to a defined state
  6. Interfacing with low power signals
  7. Adjustable power supply

Section 2: Calculate LM 317 control resistance values

Our versatile LM317 can be set to output any voltage between 1,25 and 30 Volts (referenced to GROUND). The trick is to determine the values of these resistances. We do this with the help of some JavaScript or CGI. Not sure yet which one I will use.

Page created 4 January 2008,