Category: Schematic

Bench AF Amplifier 0

Bench AF Amplifier. Schematic Diagram.

The circuit… This circuit consists of just a few discrete components and one common IC amplifier – the LM380N. It’s simple, cheap, quick to build and works well. I built mine in a steel,...

Hi Z Microphone Preamplifier Schematic Diagram 0

Hi-Z Microphone Preamplifier. Schematic Diagram.

This preamplifier for a high impedance microphone was built into a Harris limiter/compressor which needed a line-level input. Its response is essentially flat from 20Hz-30KHz. The 10uF capacitors are 25v Tantalums, the .01uF capacitors...

Simple CW 10 m TX 0

Simple 10m CW Transmitter. Circuit Diagram.

The original circuit by the late Doug DeMaw W1FB, differs slightly from the one shown here. Two immediate differences are: A regulated DC supply for better frequency stability and a 2-pole low-pass filter for...

Variable Power Supply Unit. 0

Variable Power Supply Unit. DIY.

This little circuit is a copy of a design which was built around twenty years ago. The heart of the unit is based around a 723 regulator chip. It has variable voltage and current...

6m to10m converter 0

6m to 10m converter

This circuit is based around mixer/oscillator IC2. A 50mHz signal is fed to pin1 input of IC2 and mixed with the local oscillator injected at pin7. The resultant output is the antenna frequency minus...