Questions tagged [ohmmeter]

An ohmmeter is an electronic device which measures resistance in an electronic component or circuit. It is composed of a ruled scale with an indicator needle or digital display, a range selector, and two probes.

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Reading of megohm during ground check

During the check of pins on connector with a multi-meter, one of the pins that goes through the relay to provide ground signal, I am getting 8MOhm (8 megohm). I should not be getting anything on that ...
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My ohmmeters don't behave as the book “make: electronics” describe

Here's the (low end) devices I own. One is an HoldPeak HP-90EPC, the other is an GBC KDM-110 I am following the book "Make: Electronics" by Charles Platt and I am at the very beginnings, where it ...
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144 views

Is this transformer working?

I found this transformer and I am not sure if it is working. I am confused with the multimeter readings. For example: when I am using the buzzer option to check the connectivity it buzzes when I ...
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55 views

Scaling up NTC measurement through Multi-Channel Ohm meter

For a test bed, we want to measure temperatures with NTC sensors (~10kOhm at RT) for the range 10°C to 70°C. Our test machine accepts auxiliary signal through CAN-bus, so we used a Raspberry with a "...
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432 views

Simple, low precision, milliohmmeter

Would like to have a simple milliohmeter for car wiring checking. Precision is not important, it's not about 3 vs 4 mΩ, it's about 3 vs 30 vs 300 mΩ. Simple idea is a 1A floating current source (2 ...
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Moisture Sensor Resistance

I have made a soil moisture sensor by taking two lines of Veroboard and soldering a wire to each line. The theory is that the resistance will change with the moisture - resistance dropping as the ...
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505 views

Shunt ohmmeter question

I have a question concerning this shunt ohmmeter: If we only want to use the \$R \times 1\$ gauge, we have the following circuit: I want to know what indication would appear on the ohmmeter if I ...
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365 views

Testing a Bipolar Junction Transistor using an analogue ohm-meter?

This video says I should see ohmmeter deflection with an NPN transistor, placing positive probe on the base, and negative probe on collector or emitter. A BC547 NPN is giving me opposite results - ...
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433 views

What might cause a fluctuating resistance of a generator winding?

Before assembly of a machine that contains a three phase generator I check the resistance between the 3 phases of the generator with an ohmmeter. The generator is kept stationary and the temperature ...
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644 views

How do I measure the error of my ohmmeter

I have to do an Ohmimetro to a college assignment, but I don't know how discover the measure error of my circuit. When we buy a multimeter, the equipment has a measure error calculated by the ...
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176 views

Can an inductive load mess up an ohmmeter's reading

I've found a something quite odd with measuring the resistance of a 36uH inductive load (see this earlier question). I can measure the resistance, which is quite low, but then disconnect the probe and ...
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Multimeter shows 50 M Ω between 9V battery terminals. Why so high?

I'm using my digital multimeter to measure the resistance between the terminals of a 9 volt battery i had lying around. Why does it read as 50 M Ω? Why is the resistance so high? I would think that ...
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Large resistance of diodes measured by ohmmeters

Many multimeters have a diode mode and I have always used this mode to measure diodes. Today, I happened upon a Fluke article that explains you can use the ohmmeter mode to measure diodes as well: ...
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497 views

Alternative to diode to allow uniform and predictable voltage drops or On resistance

I'm trying to design a relatively high accuracy auto ranging Ohmmeter. A typical Arduino example can be found here: http://www.circuitstoday.com/ohmmeter-using-arduino The problem with this design ...
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167 views

Low power ohmmeter

I need to monitor a variable resistor R1 (7.5 to 8k). The circuit runs from a coin battery. For now I'm using a voltage divider R1 and R2 = 10k, and it uses 3.3V from the battery. The middle points is ...
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629 views

How does an ohmmeter measure different resistances?

An ohmmeter has set of range settings for the resistances to be measured. When we switch to any range, what behavior of the test reference is being adjusted? In other words; I'm wondering if we ...