Newest circuit diagrams

Sound Operated Switch

A sound operated switch with a relay driver.

AC Current Monitor

Senses high current-flow into power cables No wire-cutting, three versions available

Two-wire Lamp Flasher

Ideal to operate 3 to 24V DC existing on-circuit lamps. LED operation is also possible

Doorbell for the Deaf

This circuit provides a delayed visual indication when a door bell switch is pressed. In addition, a DPDT switch can be moved from within the house which will light a lamp in the door bell switch. The lamp can illuminate the words "Please Wait" for anyone with walking difficulties.

Tone Control

Based on the classic Baxendall tone control circuit, this provides a maximum cut and boost of around 6dB at 10K and 50Hz.

LED Torch

A common problem with small torches is the short life-span both of the batteries and the bulb. The average incandescent torch, for instance, consumes around 2 Watts.

LM317 Regulator Tester

This is both a useful and very handy test circuit for quickly diagnosing faulty regulator IC's. In addition, Abu has a novel and innovative solution to quickly connect all 3 regulator pins - just by using an 8 pin DIL socket.

IR Remote Control Modulation Detector

A circuit to extract and measure the modulated carrier of an Infra Red remote control. Note that the circuit does not physically separate control pulses from modulation, but amplifies the completereceived signal allowing the waveform to be displayed ideally on an oscilloscope or a frequency counter.

Single Zone Alarm

A single zone alarm circuit with entry and exit delay and other facilities.

Audio Level Meter

Audio levels can be monitored using a small panel meter with this circuit built from discrete components.