Obtained from a 1969 documentation, this circuit can operate at frequencies up to 500 Hz, counting up to 999. The circuit makes use of neon lamps of the time.
This 3 + 3 V symmetrical source circuit uses an old operational amplifier. The circuit is from an...
This circuit for low frequency data transmission was found in the May 1977 issue of Radio...
This circuit was obtained from an English documentation, with the purpose of carrying out the...