We found this CMOS circuit for excitation of a relay in an old documentation. The transistor is a general-purpose high voltage as used in the power supply.
This circuit generates trains of pulses in regular intervals determined by R1 and C1. The...
The first transistor can be the BF494 and the other BC548 on this MW radio found in a...
We found this circuit in a Popular Electronics from 1992. It modulates an infrared LED with a...