Analog Dial Amps-Volts-Ohms meter
This was designed, keeping in mind, that sometimes we have few components available and you could not carry your DMM somewhere, but you have to make some instrument for a quick need with what is available.
IC3 LM555 is to generate -5V from 9V. That reminds me of a story, I came across a Book called CMOS Hot Ideas of Intersil. I had a chance to observe, build and learn some things here. The ICL7107 circuit was the most fascinating, I also read the books of National Semiconductor here.
In those days small firms used to make DPM’s digital panel meters with 7107. In 1987 when i got a oppurtunity to design a DPM for a firm, I put the 555 clock in place CD4009 clock shown in intersil, to derive the -5.
Potentiometer Dial GIF for above circuit to be used to make a hand-held avo-meter is here.