Newest circuit diagrams

ZN414 Portable Receiver

An AM portable radio receiver made from the ZN414 IC. The ZN414 ic has now been replaced by the MK484 which is identical in performance and pinout.

Bedside Lamp Timer

30 minutes operation Blinking LED signals 6 last minutes before turn-off

IR Remote Control Extender Mark 3

This Mark3 version of the Infra Red extender is a special version designed to control appliances that use high frequency modulated IR remote controls.

The GEM: Class-A/AB Amplifier

The GEM is an audio power amplifier embodying simultaneously active Class A and Class AB output stages for 100+ Watts into a 4 ohm loudspeaker. The front end pcb will drive up to 100+W variants, or the 200+ Watts version into a 4 ohm loudspeaker load.

AM Transmitter

An AM voice transmitter with variable tuning. The antenna circuit is also tuned and transmits via a long wire antenna.

Electronic Doorbell with Counter

This circuit uses a synthesized sound chip from Holtek, the HT-2811. This reproduces the sound of a "ding-dong" chiming doorbell. Additionally, the circuit includes a CMOS 4026 counter display driver IC to count your visitors.

LED or Lamp Pulser

Astonishing effect. 4.5V supply

Soft Start PSU

Two soft start power supplies. The output voltage slowly increases to the desired output.

9 Volt 2 Amp PSU

A simple 9 Volt 2 amp supply using a single IC regulator.

Audio Bargraph Display

An easy to use LED bargraph display to monitor audio levels. Circuit monitors a single channel, so build two for stereo.