We found this circuit in the March 1995 issue of Electronics Now magazine. The circuit has a frequency range determined by C1 and R3. The signal generated is square.
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...