Based on the CA3161 and CA3162, this circuit was found in the July 1990 Radio Electronics magazine. The circuit is two digits only.
This circuit can function as a light alarm by changing the sound when light falls on the sensor....
In this circuit the photo-transistor signal is amplified by a Darlington step and then applied to a...
This is a traditional complementary-output transistor amplifier sourcing 2 to 4 watts to a 4 ohm...