Two-tone decoder (CB8719E)

Found in a 90s 73 magazine, this circuit uses an unusual component today which is the XR2206.

| Clique na imagem para ampliar |

741 Twin T Variable Filter (CB25604E)
This filter, which rejects frequencies around 1 kHz, was found in the August 1993 Electronics Now...
Regulator LM317 (CB22475E)
This is a voltage regulator circuit for currents up to 1.5 A with an output voltage adjustment for outputs...
Heads or tails (CB22061E)
This circuit uses an operational amplifier that is still common today. The indication is made by...