Passive tunable filter (CB7407E)

Found in American documentation from the 1980s, this circuit is a basic signal rejection filter network using only passive components.

| Clique na imagem para ampliar |

Telephone Monitor (CB12655E)
This circuit of a 1978 American publication monitors a telephone line by triggering a relay. The...
FET Transconductance Meter (CB3932E)
This interesting FET-tester circuit was obtained from an old American documentation. The bipolar...
TV Booster (CB23771E)
This old VHF TV booster that also serves FM was found in Radio Electronics magazine from April...