This circuit was found in documentation from the 90s. The transistors can be general-purpose equivalents. The circuit has two versions, one that drives LEDs and another that drives a relay as a load.
We found this circuit in an old documentation. The instrument can be an ordinary multimeter in the...
This simple electroscope with bipolar transistors is not the most sensitive, but can detect static...
This circuit was found in an old Popular Electronics. It causes an LED to pulse and, at the same...