This power supply is based on the 723 integrated circuit, which is no longer very common today. The transistor must have a heatsink and the bridge can be formed by diodes 1N4002 or equivalent.
This transistorized “grid dip” oscillator was found at Radio Electronics in June 1953. The...
This circuit has a very traditional configuration that can be found elsewhere on the site. R2 and...
This high input impedance amplifier stage was found in a 1963 documentation. The transistor...