ETI logo

Electronics Today Contents

cover of ETI issue 12

Contents for Volume 27 No. 12

Next Issue 4th December 1998

Fun with Filters

Different design compromises must be made according to the intended function of a filter, and different configurations of a given filter design are required. Douglas Clarkeson explains how filters design can be aided using standard chips such as switched capacitor filters, for which design software is often available.

s or jw - two aspects of the same problem

Martin Smith goes into some of the basic mathematics underlying filter design.


The use of semiconductor temperature measurement to control the temperature of a thermoelectric coldbox is a practical application of a technical tip from Issue 9. Keep your beer at the correct temperature for optimal enjoyment.

18-Channel Infra-red Remote Controller

Pei An describes a general purpose infra-red remote receiver which could be implemented in equipment where remote control is needed. Its partner is a handset transmitter using the BL9148/BL9150 chipset.

Timing in Electronics (Part 6): counting the seconds

This month Owen Bishop describes the best way of timing periods of minutes and seconds, and adds a decoder circuit and an alarm circuit.

Professional PC-Controllable 4-Line Dot Matrix Display (Part 3)

The third and last part of Robert Coward's modular display system describes how to make up the casework and also gives advice on the in-circuit PIC programming facility, and interfacing external equipment.

Switch-Volt PSU

This bench power supply designed by Terry Balbirnie especially for home constructors provides nominal switched voltages corresponding to multiples of standard 1.5V cells will provide power for most circuits up to 12V.

Circuits for Music Lovers (Part 2)

Some more music control circuit ideas including a combined Bass and Treble Boost, a Soft Limiter and a Smooth Fuzz.

A Fishbite Alarm With a Difference

What is really going on under the water on a windy day? Bob Noyes uses tiny vibration in a fishing line under tension to detect if a fish is "trying it out" and trigger a discreet audible or visual alarm. For salt or freshwater fishing.

PIC Barcode Reader Interface

Industry makes extensive use of barcodes to identify goods. Roger Thomas explains the principles behind commercial barcoding and how to decode EAN-13 barcodes using a low cost barcode reader wand and a PIC interface to a PC.

Vulkan Gas Powered Soldering Iron

Portable soldering irons can be battery powered or gas powered. This gas powered iron proved to be reliable and versatile in use.

Practically Speaking

Terry Balbirnie describes the uses of the magnetic reed switch.

To link to back issues, go via the home page

Home   Contacts   LinksPage   Circuit tips   Latest Issue

Copyright © 1998 A. S. and H. P. Armstrong