Variable gain operational amplifier (CB8068E)

This circuit is from an Electronics Now from the 90s. It applies to almost any operational amplifier. See formulas for component calculation.

| Clique na imagem para ampliar |

Monochrome TV Pattern generator (CB9421E)
Using an integrated circuit from the time, this circuit was found in Radio Electronics from the...
Interface Shield 75491 (CB19760E)
This shield circuit is from old documentation. The operational amplifier used is not common today...
Power Grid Voltage Monitor (CB13917E)
This circuit powers a small 5 W lamp that goes out when power is lost. The circuit can use the...