Newest circuit diagrams

Universal PSU

A Universal Power supply based on the L200 regulator, which includes an outboard pass transistor to boost output currents up to 4 amps.

Coil Coupled Operation Metal Detector

A Coil Coupled Operation Metal Detector made from readily obtainable components and using an ordinary medium receiver as a detector.

Car Alarm and Immobilizer

This circuit features exit and entry delays, an instant alarm zone, an intermittent siren output and automatic reset. By adding external relays you can immobilize the vehicle and flash the lights.

Dynamic Microphone Preamp

A low noise pre-amplifier suitable for amplifying dynamic microphones with 200 to 600 ohm output impedance.

Cheap Transistor 'Beta' Meter

Measures the hfe of NPN and PNP transistors. Requires a digital or analog Multimeter.

Mini Guitar/Bass Amplifier

Output power: 6W into 4 Ohm load. FET input stage - Passive Tone Control

Cuckoo-song Generator

Agreeable, very close sound imitation. Suitable for sound effects, door-bells etc.

Two-LED Pilot Light

230 or 115 Vac mains operated. Very simple circuitry

Increasing Regulator Current

An outboard pass transistor used to increase the current output of a voltage regulator IC.

Light Detector Circuit

The circuit uses a CMOS 4001 IC. Gate U1a acts as the trigger, U1b and c form a latch. S1 resets the circuit.