This circuit is from the 80's but uses common components today. The relay is voltage sensitive according to the power supply used. Transistors may be general purpose types.
We found this circuit in the National Semiconductor Audio Handbook of 1977. The circuit produces...
This is a shunt circuit to be used on a multimeter, expanding its scales to measure high currents....
In the figure we have a precision differential amplifier found in the Linear Applications Handbook of...