This stabilized source can supply currents up to 700 mA and the output voltage is close to 15 V. a little less with the load. The power transistor must have a good heat radiator.
This circuit was found in an Electronic Design from 1967. The circuit uses two triacs being T2...
Found in old American documentation, this circuit can use crystals between 27.5 and 33 MHz...
This shield from the 60's uses a germanium transistor of the time and a common type of relay of...