Hearing Aid Amplifier (CB21797E)

This 4-stage amplifier was found in a Mullard transistor manual from 1960. The circuit has a quiescent current of only 0.3 mA.

LED Indicator (CB14962E)
This circuit uses two transistors and can be powered by just two small batteries. The frequency is given...
Transistor Microammeter (CB3921E)
This circuit consists of an adapter that allows the reading of low currents at various scales. A...
Decade neon counter (CB6618E)
Found in a 1969 documentation, this neon lamp circuit may have the number of steps increased. The power...