The integrated circuit used in this amplifier is uncommon today, since the project is from the 90s. The power is 24 V, and the gain of the circuit is 40dB. The input resistance is 1 M ohms.
This sensor circuit from a 1967 Ferranti documentation uses components from the era. The circuit...
This is the receiver for the previous circuit transmitter. Similarly, no information about the...
Found in a 90s Popular Electronics, this circuit uses two PLL tone recognizers to trigger by touch an...