Electronic Engineering Schematics
Analog Dial AVO Amps-Volts-Ohms meter - del00023
This is a Amps Volts and Ohm Meter without a Display. It has a
Potentiometer that has to be turned to make a measurement by
watching the Bridge Balance LEDs switch ON state.
The real reason of doing this is to help students understand the
various sections of parametric measurements. By building this
you will learn more about analog design and
This was designed, keeping in mind, that sometimes we have few
components available and we could be flat broke. Even that you
could not carry your DMM somewhere, but you have to make some
instrument for a quick need with what is available.
If you are out of cash or feeling like Robinson Crusoe stranded
in a place where you cant find any parts; then this is a low
cost measurement system. I am not sure how this circuit may
work, it is not tested . But i have built, repaired and designed
many DMMs. So there is a fair chance, parts of it may work
Dial AVO Amps-Volts-Ohms meter - del00023
To view circuit. Click the Link of PNG or PDF and view the
Circuit, PNG can be Scrolled with Mouse.
IC3 LM555 is to generate -5V from 9V. 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 (-3V).
This circuit is battery operated and has easily available LM324
quad Opamp and Timer LM555. Some Small signal Transistors and
Diodes. Resistors and Caps. Yet it is difficult to build and
make it work. You can even integrate a Digital or Analog meter
after you learn and gain expertize.
In those days other databooks i referred were from, TI, SGS and
Fairchild. So most of these ideas with which i
design opmaps were learning that came from their application
notes and datasheets. So read them and then you can understand
The Source File in Cadsoft Eagle - del00023.zip.
Potentiometer Dial GIF for above circuit to be used to make a
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20th Mar 2020