This untuned circuit uses one of the world's first commercial transistors, the CK722, having been found in a 1966 publication. Equivalent modern types can be used.
Originally created to feed the filaments of a 12AX7 as an audio preamplifier to eliminate the...
Found in a Popular Electronics from the 1990s, this circuit uses components from National...
This symmetrical +5 V and 12 V x 50 mA power supply with MAX610 from Maxim was found in an...