6C4

Miniature 7-pin general-purpose medium-mu single triode engineered to serve reliably as a local high-frequency/VHF oscillator, RF mixer, or small-signal audio voltage amplifier. Equivalents: 6C4WA, 6C4W, 6100, CK6100, EC90, CV133, CV4058, M8080. Real-Life Examples: Heathkit AR-3 shortwave receiver, Eico 232 VTVM meter, ARC Type 12 military aircraft navigation radio, Collins 75A-1 receiver.