We found this circuit in an Electronics Now from the 1990s. The circuit crashes when light strikes the sensor. Instead of the alarm a relay can be used to drive higher power devices.
This Testa o Croce (name in Italian) was obtained from an Italian magazine in 1994. The circuit can...
This stabilized source can supply currents up to 200 mA with the indicated transistor or 500 mA...
This oscillator does not carry any resonant circuit, except for the one formed by the crystal...