This circuit was found in a 1965 General Electric publication. The circuit can be adapted to operate with other voltage lamps.
This circuit was obtained in a 1969 Mullard manual. The transistors are from that time. The input...
This circuit with the PLL4046 was found in the October 1994 Electronics Now magazine. The...
This circuit was found in a 90s Hands-On Electronics. When a signal appears at the headphone...