The power supply for this circuit must be symmetrical at 12 + 12 V and the load must be 8 ohms. The circuit is from the 1982 SGS Linear Integrated Circuits Manual.
This 1967 Raytheon circuit uses an optical coupler of the era and has a range of 800 to 200 Hz....
This interesting digital counter with relays with complementary outputs was found in the Radio...
This circuit uses a diode as a radiation sensor. The operational ones are old because the...