Found in Electronics now from the 90s, this circuit uses a sensor from the time, which is difficult to find today. The circuit activates a sonalert-type buzzer.
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...