This dual-tuned 60 Hz oscillator was found in the Radio Experimenter Special projects of 1993. The circuit has the timing ranges given by C1 which can be changed.
This amplifier from 100 to 150mW was found in a Japanese documentation from 1967. The circuit uses...
This circuit is from a manual of JFETs and can be implemented with the BF245 and for the bipolar...
This source of some amps for voltages up to 40 V was found in an Italian magazine Elettronica...