This circuit was found in a General Electric documentation from 1970. Equivalent transistors can be used. The maximum signal frequency for the indicated components is 250 kHz.
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...