High Input Impedance 250 mW Amplifier (CB14577E)

This circuit is suggested by Motorola in its 1990 Linear Databook. The speaker (or headphone is 32 ohms impedance, and the power supply is 6 V.

LM380 2.5 W amplifier (CB10900E)
The traditional circuit was taken from a French magazine Radio Plans that no longer exists but can...
Monostable with LED Indicator (CB13595E)
This monostable circuit, from a 1977 Radio Shack documentation, uses a 7400. The time is given by the...
Night Switch (CB12701E)
The circuit shown in the figure activates a small indicator lamp that will start to flash when the...