This mixer with 20 dB gain per channel uses RCA's CA3048 integrated circuits. We found it in the July 1971 Radio Electronics magazine. The power supply does not need to be symmetrical.
This circuit is given in two versions, having been found in a publication from the 90s. The second...
This circuit was found in an ancient American documentation. Used integrated circuits are uncommon...
This Texas Instruments circuit uses a phototransistor to fire a TTL trigger port. Other...