Audio amplifier 741 (CB20478E)

This low power audio amplifier was found at 1992s Popular Electronics. Transistors are general purpose common types.

Two-stage RC amplifier 2 (CB7467E)
This circuit was found in a 1977 Radio Handbook. Equivalent transistors can be used. The formula...
Double tuning Pre-selector (CB9169E)
This circuit was found in a Popular Electronics from the 90's. The circuit has gained 10 to 20 dB...
Transistor Voltmeter (CB1412E )
The purpose of this circuit is to increase the sensitivity of a common multimeter in its voltage...