Newest circuit diagrams

Adjustable Power Supply with Charger Output

This power supply has adjustable and charger output. The charger circuit can be use for cellular phone. The adjustable output serves as multipurpose power supply. It can handle a 1 ampere current. The 317 must have a heat sink.

Mains Remote-Alert

Beeper and/or LED remotely-operated via mains supply line Simple circuitry, easy to build units

Periodic Timer

A switched timer with equal make and equal space periods timing adjustable from over 6 minutes to 38 minutes.

120 and 240Vac LED Voltage Indicator

Useful for power lines control. Simple, transformerless circuitry

Magnetic Gun

Picured in Figure 1 is a miniature magnetic gun. When optimally tuned, it will propel a small slug about 1.5 metres high, or 2.5 metres horizontally.

Fine Control SuperBright LED Pulser

Four timing controls - 12V supply. Suitable for Halloween or Christmas props.

Op-Amp Mic Preamp

A high quality microphone preamplifier using a single power supply, suitable for dynamic or electret microphones. The op-amp used can be any low noise, high performance type, e.g. NE5534,TL071, OPA 371 etc.

200mW Stereo Amplifier

A small battery driven amplifier with 200mW output. This is a suitable amplifier for portable radios and other battery powered equipment.

Add-On Current Limiter for Power Supplies

This circuit allows you to set a limit on the maximum output current available from your PSU. It's very useful when you power-up a project for the first time - or carry out a soak-test.

Guitar Preamp

A pre-amplifier for electric guitars. The guitar pickup is high impedance, therefore good quality screened cable must be used between guitar pickup and the preamp.