Meter Tester


Posted on Sep 24, 2012

This unit uses switches and resistors to provide a number of current ranges. It allows you to test most of the meters availabl


Meter Tester
Click here to download the full size of the above Circuit.

e at surplus outlets, and without damaging the sensitive movements when you have no idea of internal resistance or full-scale current of the unit. Ml is a multimeter set to measure current, and M2 is the meter-under-test. Starting with SI set at the maximum resistance and S2 open, decrease the resistance setting of SI, fine tuning with R12, until M2 reads full scale. Then, read Ml. It will tell you the full-scale current for the unknown meter. As the meters are connected in series, the same current flows through both. Now, close S2 and adjust R14 and R15 until M2 reads exactly mid-scale and Ml reads the same current as determined earlier to be the maximum current for M2. Half the current is flowing in M2 and half is going through R14 and R15. The voltage drop is the same across the meter and R14 and R15, because they"re in parallel. Thus, the sum of the resistance of Ru and ii5 is the same as the internal resistance of meter M2. If the internal resistance of M2 is less than 470, set R14 at maximum resistance and close S3. Readjust R14. Both R14 and R12 should be linear-taper potentiometers.




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

450 watts / 3.5-30 MHz Linear amplifier
Car 20W audio booster amplifier
FM Moulator with IC 555
Astable Multivibrator Using 741 Op-Amp
audio How to create a multi-extension intercom system using wired phones
Keyboard Interfacing to 8051
A Very Simple LED Tester
Complete SS Laser Power Supply Schematics
Small TV terminal with ATmega8 microcontroller
CAPACITANCE METER



Top