This circuit was found in a Radio Electronics from 1970. The coupler with LDR is from that time, but the circuit can be adapted to use modern components and act as a shield.
The integrated circuits used in this 1999 project are not very common today. However, they can be...
This 3-digit thermometer, suggested by Texas Instruments, uses 3 integrated plus the display, with...
This circuit is from the National Semiconductor FET Databook. The coil data is provided with the...