Originally indicated as an alarm alert in a 1990s US publication, this circuit can be used as a shield to control a strobe lamp. The sensor is a optocoupler with LDR.
This good quality audio amplifier with an output of about 10 W with the original transistor was...
The presented circuit can be implemented with a BC548 and for larger currents a BD135 can be used....
When the input voltage is higher than 2/3 of the power supply voltage the green LEDs glows. When...