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 metronome was found in a 1979 publication, but it can be assembled more easily with the BC548...
Wired to the output of any amplifier this circuit makes an incandescent lamp flash according the...
This type of circuit, even with the same configuration, appears several times on this site. The...