Welcome!

This circuit will allow you to place a phone call on hold and if you wish to have them listen to music while they are on hold.... [read more]

This circuit is intended for children fun, and can be installed on bicycles, battery powered cars and motorcycles, but also on models and various games and toys. With SW1 positioned as shown in the circuit diagram, the typical dual-tone sound of Police or Fire-brigade cars is generated, by the oscillation of IC1A and IC1B gates. With SW1 set to the other position, the old siren sound increasing in frequency and then slowly decreasing is reproduced, by pushing on P1 that starts oscillation in IC1C and IC1D.... [read more]

This is a programmable clock timer circuit that uses individual LEDs to indicate hours and minutes. 12 LEDs can be arranged in a circle to represent the 12 hours of a clock face and an additional 12 LEDs can be arranged in an outer circle to indicate 5 minute intervals within the hour. 4 additional LEDs are used to indicate 1 to 4 minutes of time within each 5 minute interval.... [read more]

This circuit is the opposite of Repeating Timer No.5. It will only begin to operate if the temperature falls below the preset level. Again - the variable resistor (preset) lets you choose the temperature below which the timer will function.... [read more]

Firecrackers are normally ignited by using a matchstick or a candle. You have to run away quickly after igniting the fuse of the firecracker. This method of igniting firecracker is unsafe, because the danger of the firecracker bursting before you reach a safe distance is always there. The device described here uses remote control, usually used with TV receivers or CD players, to burst the fire-cracker. Thus the firecracker can be ignited from a safe distance using the circuit described below in conjunction with the remote control.... [read more]

A simple test circuit to fault find audio and radio equipment. Can be used to inject a square wave signal, rich in harmonics, or used with headphones as an audio tracer.... [read more]