Found in a 1967 Electronic Design, this circuit changes the phase of a signal in 8 different ways, given by the formulas next to the diagram. Equivalent general-purpose transistors can be used.
This circuit was found in the December 1992 Radio Electronis magazine. R2 is an NTC, there is a...
This passive tuned circuit was found in a 90s Popular Electronics. The coils must be according to the...
This circuit is from 80's Linear Technology documentation. Equivalent operational amplifiers can...