This very high input impedance JFET circuit was found in the 1995 Encyclopedia of Electronic Circuits Volume 5. The JFET is a general-purpose transistor as is the output transistor.
Found in a Popular Electronics from the 90s, this circuit reaches 100 kHz and battery power is...
This high current regulator with low voltage drop was found in the datasheet of the used...
This circuit has a gain of 34 dB and a good power to be used as an audio booster in cars. The...