60's crystal radio (CB22171E)

Found in an English publication from the 1960s, this circuit uses period components, including the commercial grade coil.

Frequency Switch 1N4148 (CB24706E)
This circuit uses a common diode to switch a high frequency signal. The circuit was found in the...
Voltage to Frequency Converter (CB13456E)
This circuit was found in a 1974 publication. It converts the applied voltage into pulses of...
Modulator for rectangular signals (CB21630E)
Based on TTL logic this circuit can vary both the frequency and the pulse width of a rectangular signal....