Questions tagged [multimeter]

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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44 views

Completing Circuit When Testing Using Ammeter with Fuse Adapter

I am using a multimeter to determine which piece of equipment on my vehicle is causing a parasitic battery drain. I purchased a fuse adapter and have connected it to the multimeter as in the following ...
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72 views

Multimeter seems to be giving incorrect mA reading

I'm measuring the current drawn from the negative battery terminal of my car battery. I am not sure if the correct reading is 0.16 A or 1.6 mA. I tested with my multimeter on both 10 A and mA ...
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Am I testing diodes properly?

I decided to test some diodes that I have, using a multimeter to measure their forward bias voltage. I set my multimeter to voltage test and connected the diode across: I tested a bunch of different ...
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65 views

I want to measure 50 miliamps by multimeter which range i should select?

I have a multi meter I want to measure DC 1-50 milliamps which range I should select by the knob? Also where I need to plug in 20A or mA?
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89 views

Discharging capacitors with a multi-meter in diode mode

Recently I encountered this "trick" where you use a multi-meter in diode test mode to discharge a large electrolytic capacitor. I feel that this cannot be a good practice, but the people who were ...
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36 views

How to check (6 pin) PCI-E power rail on a pc powersupply?

Could anyone tell me if and how i might verify whether or not a PCI-Express 6 pin power lead on a PC is outputting correct voltage(s) ? A while back, I decided to try to refurbish a graphics card ...
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3k views

What does the multimeter dial do internally?

Everyone who has ever handled a multimeter is familiar with these dials. The position of the dial indicates the maximum range of the quantity that can be measured. But why are we required to adjust ...
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94 views

Measure 10kV with 600V rated multimeter [duplicate]

My multimeter is rated for 600V but I need to measure a 10kV AC source. I was thinking of building a voltage divider but I wouldn't know how many resistors it would take to safely measure this high of ...
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52 views

How to test a TRIAC with just a digital multimeter and no external circuit

I need to fix an electric kettle and would like to test the health of the TRIAC BTA20. How would you test this component health with a digital multimeter - without any extra components and ideally ...
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85 views

Why am I reading 22VDC / 69VAC when measuring between myself touching a MacBook and ground?

If I put the positive probe of my multimeter on earth, and touch the negative probe with my hand, while another hand is touching the metal surface of my MacBook, I get around 22VDC or 69VAC. I cannot ...
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186 views

Why so much variance in the continuity beeper threshold? How do these beepers work anyway?

In this answer it is mentioned that the EEVBlog-branded BM235 meter has a threshold of between 30 and 480 ohms for its continuity beeper (as seen on page 25 of the datasheet). My first thought was "...
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Is the continuity test limit resistance of a multimeter standard?

The continuity shows us the shorts, but many times I guess, even if the wire has a resistance of up to 50 ohm, the continuity will beep to indicate a short. Is it always 50 ohm, or what parameter ...
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82 views

Solar cell outputs full voltage but barely any amps

So I've asked a similar question in the past, but I'm still curious about something. On a fully sunny day, the solar panel tops out at 5.5v @ 260 mA. On overcast or cloudy days, the voltage stays ...
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130 views

How do digital multimeters measure capacitance?

How do digital mulitimeters (DMM) measure capacitance through their typical 10M Ohm input/output impedance? Providing a logic level of 3.3V, attempting to measure 1F would mean a time constant of ...
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72 views

What does DC voltage reading from a DMM mean?

When a DMM is set to measure DC voltage, does a read-out value correspond to an output of the ADC inside the DMM, or do multiple ADC outputs are averaged over a time interval and then converted to the ...
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64 views

multimeter, current measurement (beginner)

From this little circuit I try to calculate the current for Ic, Ib, Ie. For Ic , I put the multimeter on 20mA and positive wire connected to 10A and I got 0.01 ... 10mA ? for Ie it is the same (Ie = ...
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39 views

How to measure current in very low duty cycle circuit with DMM?

My circuit has 4Hz 50% duty cycle. How do I measure the average current using a DMM? I have a Fluke 87 DMM. It has an average setting but for 100 ms which less than one complete duty cycle. My ...
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45 views

Why is there a positive body voltage when grounded, but none when not?

So after reading about earthing and earthing mats, I decided to make myself a very basic one for cheap to test the concept before jumping in with purchasing more sophisticated products. Here's what I ...
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64 views

How do I find the right resistor for an LED panel? [closed]

I purchased one of these cheap LED panels to light a room. One review suggested that it's important to put a resistor on it, to keep it from frying itself. But, he didn't list what resistor to use. ...
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70 views

LED intermittently fails but works when voltmeter applied

I have an LED in a home project. It's in a simple loop with a resistor and the GND and V+ ends connected to appropriate pins on a microcontroller. The LED works properly for extended periods of time ...
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2answers
61 views

Diode meter of my DMM does work for red LEDs but not for white LEDs

I have a diode meter on my DMM Powerfix Profi and I want to measure the forward voltage. (actually it is not so profi at all). So I tried the steps needed, and found the Vforward of a red led to be 1....
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112 views

Resistance reading on digital multimeter

I'm working my way through a beginners electronics book (to be specific it's 'Starting Electronics' by Keith Brindley). I've got up to the second chapter which introduces resistors and their colour ...
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150 views

How can a multimeter measure current while being parallel to the element

An ammeter is a low resistance device connected in series with the element through which we want to measure current However, a multimeter is connected in parallel with the element under observation ...
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1answer
116 views

Can I use a multimeter to measure audio signals by testing amperage or voltage?

I'm in the process of adding a subwoofer to my car. In doing so I spliced in a T harness to audio wires from the head unit and routed the wiring to where I Will be placing the Amp. I tested the ...
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83 views

powering an old 9V multimeter with a 6x AA battery pack

I have an old Nimex NI2100 multimeter that is working fine with 9V batteries. Btw i'd like to power it with 6x AA batteries instead so i've bought a battery holder and wired like this: I've checked ...
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1answer
151 views

Why do two different multimeters show completely different resistance readings?

I just received a brand new Brymen 869s and I'm concerned it may be broken as it's giving a strange reading. When measuring a 100k 0603 resistor which is soldered into a PCB (forming part of a ...
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72 views

Ammeter scale, not sure what my amp reading is

I have a basic multi-meter that I am using to measure amp on a load. I am trying to figure out how much amps my small entertainment system draws. (LCD TV, PC, speakers.) I want to build a small DC ...
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2k views

Determine voltage drop over 10G resistors with cheap multimeter

I have two 10G resistors connected in series with a 3V battery. I want to determine the voltage drop across one of them, which of course is 1.5V. When I use my multimeter to check the voltage drop, it ...
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1answer
61 views

Measure voltage of the panel light bulb inside a vintage radio

I'm new to Electronics. I have recently received a vintage radio Pioneer TR-305. I am trying to replace the panel light bulb inside this radio. I opened the radio panel and found the bulb soldered ...
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1answer
79 views

Wheatstone Bridge - strain gauge sensor

I'm trying to optimize a Wheatstone bridge with a strain gauge sensor and I'm considering all possible wire resistances. The circuit is shown in the following figure: I don't understand the comment ...
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2answers
105 views

How to use a multimeter to test the resistance of my tongue?

I just purchased this cheap-o multimeter: https://www.amazon.com/AstroAI-Digital-Multimeter-Voltage-Tester/dp/B01ISAMUA6/ref=sr_1_1?keywords=astroai+am33d&qid=1551837071&s=gateway&sr=8-1 ...
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70 views

Multimeter Giving Wrong Temperature Probe Readings [closed]

I want to ask a question about my multimeter, it's new but when i plug in the temperature cable - red to VOhm, black to COM and turn to tempreture it displays temp of period(-886°C/-900°C), and when i ...
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58 views

Circuit Failure How to fix it? [closed]

I'm sorry I am very specific here, I have a problem with the charger of my motorbike dashcam and I hope you can help me fixing it (see picture and video test with multimeter). I really have no idea ...
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113 views

Display input from multimeter on PC

I have opened a Multimeter (Model:DT830D) and I want to take the input that is fed to the LCD display and display it on my PC instead using the serial monitor of the arduino. But I am confused about ...
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126 views

multimeter temperature accuracy [duplicate]

I have tried searching for an answer and looked online, but I'm just getting more confused. I have a DMM that measures temperature with a thermocouple lead, with a resolution of 1 degree C (shows 020)...
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92 views

How to read a multimeter (digital) — should I get 2A readings from a couple of AA batteries?

I have been using some old multimeters in a high school science lab. We did a current an voltage reading from a AA supply (two batteries) with a variety of resistors. In some cases a 1M resistor. I ...
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240 views

Why can't I use lithium batteries in this multimeter?

I have essentially the same question as this. In that question, it seems lithium batteries are prohibited for use in the device because it wouldn't adequately warn the user that the batteries need to ...
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2answers
40 views

measuring resistance on hv transformer

I need to verify the resistance on a HV transformer that receives 208v single phase through terminal 1 and 2, or 240v through terminal 1 and 3 and delivers 4000v through terminal 4. As per the ...
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181 views

Testing crystal oscillator with multimeter crashes system

I have an old XT computer with a crystal oscillator that I would like to test. My multimeter has a Mhz setting that as far as I know should allow me to test it. (Providing the crystal is powered) ...
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586 views

Why do some multimeters have discrete ranges for measurable values and some just measure based on signal type?

I have a multimeter in my toolbox that has ranges of values it measures in dc voltage, a lot like the one below which can read DC but reads it by orders of magnitude. In order to get a proper reading ...
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112 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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1answer
76 views

Seared my circuit while checking voltage [closed]

I was attempting to diagnose a problem with my dvd player as I was not getting any power, I wanted to use my multi-meter to see where the circuit was shorting out, I set the setting on the multi-meter ...
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64 views

Measuring USB power adapter quality using multimeter

I have heard horror stories about poor quality USB power adapter. I have a collection of no less than 20 USB power adapters, most are from cell phone manufacturers and some from small projects. I ...
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1k views

Why do LCR meter manufacturers give the details of measurement frequency to us?

When you want to purchase a DMM, more probably you don't see at what frequency the DMM you considered would work, but in the situation you're considering to purchase an LCR meter, manufacturers give ...
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132 views

Continuity testing - Why does swapping DMM probes give differing results?

Continuity query - Can anyone explain this? Circuit is a simple 12v DC, wired as follows -battery pos to bulb to spst switch back to battery earth. Testing with DMM in the dedicated audible ...
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94 views

Darlington Transistor TIP142 same type but different values

I have a bunch of Darlington NPN Transistors TIP142 that are removed from two separate identical boards. The 1st one have the TO−218 CASE (left side of the image) and the 2nd the TO−247 CASE (right ...
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60 views

CB blew when trying to measure the current using multi meter. What went wrong?

I set my multimeter like this. Plug the black lead to the short tab of NEMA5-15 receptacle first and the red lead to the long tab. The moment I put the red lead in, there was a big spark. The ...
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126 views

Can I use any HV Probe for a Voltmeter/Ampmeter gauge?

I purchased the multimeter pictured below for a high voltage power supply I'm working on. It's rated for 100V DC and 10A, but I hope to measure several thousand volts. Is it possible to use a HV ...
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138 views

how to avoid brownout caused by a multimeter on esp32

I am using the VOLTCRAFT VC130 multimeter for measurement of current through my esp32. The microcontroller runs perfectly with two 1.5V batteries(~3V as read by multimeter in voltage mode). But when I ...
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120 views

What is line to line voltage supposed to meter at?

I'm pretty new to this but I know that in three phase power, when I'm metering line to line its usually at 208V, but I've been told that line to line meters at 240V. I don't know what would cause for ...