This sensitive touch key appears on this website from other sources. This version was taken from a 90s American documentation. The source must not be of transformerless type.
This experimental amplifier was found in the 1960 Mullard transistor reference manual. The...
This circuit from Motorola is from 1968, appearing elsewhere on this site. The transistors admit...
This circuit triggers the LED when the monitored battery voltage drops below 9 V for 12 V...