This circuit was found in an American publication in 1966. The circuit uses a general-purpose FET that admits an equivalent. The instrument is a 250 uA full-scale microammeter.
We found this load control circuit on the power grid using a SCR and PUT in a thyristor manual...
EZP-Q metallized polypropylene capacitors from Panasonic's can be purchased from Mouser...
The circuit shown in the figure can generate signals up to 1.6 GHz. Coil L1 and capacitor C2 are...