# Tagged Questions

Single universal measurement device that can be used to measure voltage [V] and current [A] in both AC and DC, as well as resistance [Ω]. Often many other ranges are available like frequency [Hz], duty cycle [%], capacity [F], ... Most are hand held, some more expensive ones come as a bench model.

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I have load a 10nF capacitor with a bigger capacitor of 100 uF. Both have the same voltage but when I measure the voltage of my small capacitor I unload it to zero... How can I avoid this effect ? Is ...
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### why do i measure a potential difference when I put my two electrodes in a water bottle?

I have a multimeter adjusted in DC tension mode. When I put my two wire connections inside a water container, I measure +120 mV or sometthing less but never zero. Why do I measure a potential ...
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### Supercapacitor ESR

I am trying to automate a method of testing the ESR of many super capacitors simultaneously. I have read that a good method of measuring the ESR of capacitors is to apply a square wave across the cap ...
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### Measuring surface and volume resistance of a cylinder with a multimeter

I'm trying to measure the surface and volumetric resistance of a cylinder shaped object using a multimeter. At what points should I place the probes, and what formulas should I be using to calculate ...
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### How to check earthing using handheld digital multimeter?

I would like to know to how to check for earthing (electrical) ina house using handheld DMM.
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### Help diagnosing problem with multimeter voltage readings

I pulled out my digital multimeter (RSR 1007) that I hadn't used in a while. It measures the resistance correctly, but the voltage reading is odd (note I've correctly set the range, DC/AC, it has a ...
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### How to check for short circuit in coil

I have 70 turns of enameled copper coil, 1.25 mm diameter and 25.4 m in total. I wound it on top of eacher and soaked the whole thing in a thermally conductive compound. What I fear is that by ...
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### How to measure current with a multimeter? Currently getting inconsistent measurements

I have a current controlled power supply giving out 8 A (at least that's what I'm setting), plugged into a cable (call it #1) which is then connected via screws&crimps to a copper coil (call it #2,...
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### Multimeter reading 0 and drawing too much from DC power supply

So I've got a circuit that requires both 5V and 3.3V so I bought a 5V 2A AC/DC converter from a store, which I will add resistors to later for the 3.3V. Before I connect it to my circuit, I wanted to ...
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### How to use a continuity test to differentiate between wires? [duplicate]

I'm trying to repair my headphones with a broken jack. I just purchased a replacement TRRS jack, and now my problem is knowing the function of the five different wires in my earbuds. How can I use a ...
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### Voltage Divider producing unexpected voltage

I am attempting to create a voltage divider that create 4.5 volts from a 9v battery. Using the voltage divider equation 4.7k / (4.7k + 4.7k) ) * 9v = 4.5v, I ...
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### I fried my multimeter while connecting it to AC

I just bought the multimeter "Multimeter Digital MAS830L" because I wanted to learn about electronics. INSTRUCTION MANUAL HERE. Well, I've read the manual and it said clearly : Alternative ...
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### 240 V instead of 230 V on a true RMS multimeter

I'm a beginner in electronics, and I've recently got myself a UNI-T UT61E multimeter, which is marked as true RMS. I stuck its probes into a mains socket and I was expecting 230 V (Europe/Poland) but ...
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### What is Full form of hFE of a digital multimeter?

In digital multimeter, there is a transistor-check function, and there is a term hFE. I do-not know how-to use-it, however, different Websites say it is a measurement transistor's gain ("the ratio of ...
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### Breadboard circuit doesn't pay attention to sensor unless attached to multimeter probe? [closed]

Basically I'm using a programmable microchip to turn motors when a QTI infrared sensor reads a black surface. The sensor is connected to an LM293N comparator so that it outputs voltage on a black ...
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### How to run ammeter in low resistance?

I need to measure current in a small electromagnet powered off 3 x AAA batteries in series. This is the manual for my multimeter. When I run this multimeter in series and try to find the current, the ...
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### Using a voltmeter to measure RMS value of a sine signal with a DC offset

Imagine you have a periodic signal F which is nothing but a sinewave (S) plus some DC offset (D). Here is an illustration of such signal: Imagine I want to measure the RMS value of this signal F. ...
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### Using a multimeter to see if ground is connected

I've been diagnosing a problem with a relay on my car. One of the pins in the socket that the relay goes into controls the ground for the throw of the relay. When the car's computer wants the relay ...
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### A DMM low current measurement question

I'm stuck with a question when reading a textbook: The question is a situation as follows: The very high internal resistance of digital multi-meters, in their voltage measuring ranges, can be used ...
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### Multi-meters/voltmeters batteries and resistance measurements

In a popular text it is written: "Multi-meters also have one or more batteries in them to power the resistance measurement. By supplying a small current and measuring the voltage drop, they measure ...
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### Measure high voltages with a multimeter

My multimeter is rated to 600V. How can I readily (and safely) use it to measure higher voltages?
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### What is the difference between a multimeter with RMS and one with True RMS?

I am looking for multimeters. I am only a beginner in electronics, but I want to buy one that will be good enough for me for a while. I found a multimeter that measures True RMS, and another one that ...
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### Different amperage with a normal and a hook Multimeter?

I am measuring the electric power (P = VI) in a gear-motor. I measure it of two ways. One way is measure with a multimeter the resistance of the motor, then with V=RI, I measure the current, then I ...
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### Which Multimeter is correct?

I have two Multimeteres that I'm using to measure resistance of a 10 Ohm resistor. Now, when i measure with the first one it's showing 10.2 Ohms while the other is constantly changing values from 9.9 ...
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So i got a multimeter from a friend for free. This is the one: Multimeter Info In the manual of the multimeter it says that the lowest resolution of DC Voltage is 0.1 mV. does that mean that i can ...
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### Two multimeters in continuity mode, only 1 buzzer

I have two identical digital multimeters both with new batteries. I set both to continuity mode and connected the leads to each other. Only one of the meters buzzers went off. They both work ...
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### What features give reason for such a wide range of prices for digital multi-meters?

Ever since high school, I've been using the same multi-meter. It works well for low voltage purposes, but I'm scared to use it for anything else (high voltage, unless it's a little zap from an ...
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### AA battery current

For some reason whenever I play with a multimeter it always gives me results I never expect. In this case I am attempting to measure the current of a AA battery. I have the multimeter set to 10A on ...
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### Redirection of electrical current

Sorry if this is about the newbiest question on this site, If I were to draw a graphite trace on a piece of paper (which from what I know would have some amount of resistance), and connect a ...
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### Strange current reading, LED's in series

I have a 19.4v/2.37A power adapter. I have 5 LEDs (3.2v-3.4v 20mA) connected in series. When I measure the current, the reading says 0.08A, which is total of 4 LEDs, not 5, but close enough. Strangely,...
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### DC Variable power supply fluctuating? (ATTiny85)

I hooked up an ATTiny85 to my computer using an avrisp programmer, with a red LED on PB3, a 4.7k ohm pull-up resistor on reset, and a 180 ohm resistor in series with the LED on pin 3. I was able to ...
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### How to make ammeter with arduino?

i'm interested to make ammeter from arduino. So, i have 70A/50mV shunt resistor and wiring it into arduino. From my schematic, Is this possible to meassure the current from 12V battery?If it possible ...
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### voltage drop when probing a NPN transistor's emitter to collector, collector to emitter for PNP

I have some old 2SD1785 and 2SB1258, NPN and PNP transistors that I pulled off of a car audio amplifier. Using this site, I tested the transistors in question and find that they fail on the test on ...
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### Why did sparks fly when testing outlet frequency?

I'm using a multimeter (Mastercraft 052-0052-2) and I decided to see if the frequency of an outlet would read 60hz. I switched my multimeter to the FREQ setting and plugged the RED test lead into the ...
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### Why isn't Ohm's law working for this simple circuit?

I have a 70W 12V-500V DC power converter, and something in these pictures is not adding up. I run the 500V output through a high-voltage 332kΩ resistor. Now, using the left multimeter I ...
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### What is the peak - peak voltage of 15mV rms white noise?

I've been experimenting with zener diode based noise sources. I have such a source for which I want to determine the peak to peak noise voltage. I've measured the noise with my trusty multimeter and ...
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### How do I identify a burnt out component? [closed]

I was given a project completed by another group, they had left school and I was taking over the project from them, with the information that it is not working properly because "something burnt out or ...
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### Calculating resistance with a multimeter

I recently took on the job of working on someone's amplifier. There was a burnt smell coming from it. I found the pieces of the puzzle that were fried and replaced the ones I could, two diodes and two ...
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### Calibrating a multimeter without another multimeter

I have a hand-me-down multimeter from my Mom made in the 80s. I don't have another meter that is good enough to be used as a calibration standard, however I do have a few reference chips and precision ...
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### How to measure resistance across a capacitive load using an Agilent 34410A in GPIB mode

I'm trying to measure resistance across two test points in a circuit that has an overall capacitive load. This is for a very specific application and it is to ensure there are no shorts in the circuit....
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### Multimeter exploded during ACV measurment - What did I do wrong?

simulate this circuit – Schematic created using CircuitLab A DT-830B meter. I bought a new transformer, and I was trying to measure the output voltage. I plugged the probes on 'VΩmA' (not 10 ...
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### Have I damaged my multimeter by applying voltage in resistance mode?

I have an VC97 digital multimeter. In resistance mode, I applied the multimeter leads to a battery with a 4.2V charge. I did this twice, and also did so in capacitance mode. I didn't notice any ...
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### How to measure a BC-547 transistor's details?

I am new in electronics. What I am trying to do is measuring everything of BC-547 transistor's details from a basic circuit design practically. I want to measure as example: collector-emitter voltage,...
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### Battery voltage increasing while measuring (NiMH)

I was going through conditioning for a NiMH battery pack (12 x 1.2V, 1500mAh cell) and decided to check the cell voltages. I noticed that the measured voltage, with a multimeter, increased over time. ...
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### How Cheap AC Clamp Meter Reading on DC Current? [closed]

Harbor Freight's cheap CEN-TECH clamp meter does register on DC wires. For example, 12V powering an inverter at about 10 amps current DC from the battery to the inverter reads +1.68 amp then +1.52 ...
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### Why won't this bulb light when I put the multimeter in series?

It lights here with no multimeter, this is fine But if I replace one of those wires with the multimeter, connecting the multimeter in series, then the bulb doesn't light. I am wanting to measure ...
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### Common voltage when use a battery powered DMM to measure a voltage

I'm a little confused by the common-mode voltage in this situation: Assume you use a DMM to measure a signal generator's output voltage, the signal generator is grounded, apprently the DMM is not. If ...
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### Voltage sensing using Arduino with and without common reference

I wish to make a voltage sensing circuit (range -15V to +15V) using an Arduino's ADC. The problem is that since this circuit will be part of a much larger circuit in which the Arduino is performing ...