Simple 5V regulator (CB8815E)

This simple 5.6 V regulator circuit was found in a 1966’s Philips. The zener can be changed to obtain other voltages.

FET Gate Dip (CB1467E )
This circuit is a variation of the common grid dip meter, having been found in a 1975 publication on FETs....
Sharp Notch Filter (CB6722E)
This circuit was found in old documentation, but the setting applies to any operational. Resistors...
Variable Active Cycle Frequency Doubler (CB5027E)
This circuit was found in an Electronics World magazine from 1990. The circuit can be mounted...