Found in the May 1971 Radio Electronics magazine, this is the circuit for a commercial high-impedance instrument. The circuit uses 4 transistors and is powered by 2 9 V batteries.
This circuit was found in a 1982 documentation. It uses only one integrated circuit and can be...
Only those who know the secret activation code will be able to turn on the device connected to...
This 2 meter (144 MHz) preamplifier is intended for use with portable transceivers. The...