Radio with amplifier (CB20486E)

We found this circuit in a publication of 1991. The audio amplifier is an operational that admits equivalent.

Rhythmic Light (CB6702E)
Found in an Electronics World of 1969, this circuit causes a light bulb to flash along with the...
Blown fuse indicator (CB22129E)
This car circuit can be used in other applications with the proper choice of resistor. We found it in...
Digital amplifier 7400 (CB22432E)
This simple TTL digital amplifier uses NAND gates and a high impedance speaker. ...