Quad FET mixer

Saw this mixer here (google translation – the original website is in Japanese).It looks quite neat! The entire website has

Mixer circuits

Most modern mixer information these days concerns the Gilbert Cell active mixer, but these are alternative active mixers, snippets from

Tablet cover part 2

I decided on a book type cover, so the following shape was laser cut in leather.   CAD file is

Tablet cover

A tablet is ideal for portable use, yet it was hard to find a decent case. This is an attempt

VNA parts list

The parts list here is the digikey parts list . It contains everything needed, except: 1. Transformers – these were

Electret mic amp

High sensitivity (36dB gain), tested for low harmonic distortion and flat frequency response (1dB down at 40Hz, flat past 30kHz).