The operational amplifier and the sensor used in this National Semiconductor circuit are not common today, but the configuration can be adapted to use current components.
This circuit has a full scale of 1 kW, being indicated for the 110 V power grid. Adaptations can...
This crystal filter is normally used in receivers and the frequency depends on the crystal used...
This simple 2004 circuit uses a common sensor used in television and other equipment. It checks...