This high impedance step suggested by an English publication can operate up to 1 MHz with 1 V rms output. Input impedance is 1 M ohm.
Found in a 1967 US magazine this circuit generates positive and negative voltage pulses from a...
This audio mixer was found in an old American documentation. The potentiometers are 1M and the...
In this circuit of a 1968 publication the unijunction may be 2N2646 and the transistor BC548. The...