This Nixie pipe circuit was found in 1965 documentation. Note the high supply voltage. Appropriate transistors of the time were used.
This circuit can be implemented with other operational amplifiers. The formulas for calculating the...
This circuit is from a 1953 publication, consisting of an AM radio with 3 germanium transistors that,...
The sensor of this circuit is a common silicon diode and it directly drives a small cooler with a...