Using L144 operational, this circuit applies to other equivalent operational. The circuit is from a documentation two years 90. The power supply must be symmetrical.
Suggested by General Electric in a 1965 publication this circuit uses a light bulb. Can be changed...
This circuit from the 40's is a conventional analog multimeter with several scales. Its accuracy will...
This circuit for old telephone lines was found in the March 1997 issue of Electronics Now...