Analog Frequency Meter 555 (CB22164E)

This low frequency analog frequency was found in documentation from 1989. The circuit has 5 scales, and the op amp can be replaced by equivalent.

50 mW Amplifier (CB24449E)
This low-power transistorized amplifier was found in documentation from the 90s. The circuit uses...
Metal Detector (CB12077E)
This circuit is from Popular Electronics from March 1991. It can still be assembled with the...
Symmetric Power Supply (CB15712E)
The voltage of this symmetrical power supply depends on the regulating integrated circuits, which...