Null Indicator (CB21930E)

This bridge was found in a Raytheon transistor manual from the 1960s. The transistors are germanium from the time.

Biquad Filter LM148 (CB4012E)
The circuit is from the 1990 Motorola Linear Databook. The circuit can be implemented with other...
Power control with triac (CB21467E)
Found in a 1967 RCA power manual, this circuit uses an ordinary neon lamp to fire a triac. The...
Precision Current Source (CB21052E)
Found in National Semiconductor documentation from the 1990s, this circuit employs basic...