This circuit with 10 MHz and 1.25 MHz TTL outputs was found in an American documentation from the 1980s. The used integrated circuit is uncommon today.
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...