Using the 2N2646 this circuit was found in a Radio Electronics magazine from July 1968. The transistors are from the time and the lamp can be replaced by a high-power LED in a current version.
This simple 80's CMOS game was found in an English magazine of the time. It appears elsewhere on this...
This circuit uses as an indicator a common micrometer type VU with 200 uA of full-scale current. The...
This circuit was found in ancient American documentation. Diodes are general-purpose types. |...