Questions tagged [meter]

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35 views

How Power measured by Meters is affected by Harmonics?

I want to know how energy meters (Electro-static or electronic) measure Energy (let's assume power, ignore time) when there are harmonics present. I know what are harmonics, how are they generated ...
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0answers
10 views

Meter Panel Ground [migrated]

I am trying to have "cable" installed. The installer clamped on to the "ground" cable on the outside of my building and read 0.5 to 3.3 amps, so he would not install cable until the reading is less ...
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1answer
37 views

Multi-Conductor DC Clamp Meter

Does a multi-conductor DC clamp meter exist? Possibly using hall effect sensors in a specific orientation? I typically work with 24-28V DC solenoids valves & pressure transducers with 2 and 4-...
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0answers
35 views

Analog VU meter with 1 watt lm386 amp

I am building a small cigar box speaker with an lm386 and think it would be cool to have a working analog VU meter on the front. There are obviously a lot of cheap ones from China which I would be ...
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4answers
294 views

What are these transistors doing and how are they working in this VU Meter?

I was thinking of making KITT's voice box from Knight Rider, which is essentially a VU meter. I did some researching and found an appropriate IC, LM3916, http://www.mouser.com/ds/2/405/lm3915-443929....
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2answers
175 views

Mains AC Reverse Polarity - Has this damaged my fridge/freezer PCB? [closed]

In the UK, I had a smart meter installed a few weeks ago. My 4 year old Panasonic fridge/freezer (NR-B53VW2-WB) was working fine before the electric meter switch. After the install, after the engineer ...
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1answer
165 views

Why is a clamp meter unaffected by nearby wires?

I understand a clamp meter works by measuring the magnetic field generated by current flowing through a wire. It's well known that clamping 2 wires carrying the same current in opposite directions ...
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2answers
74 views

Higher precision with less digits?

Consider an ideal digital milliammeter (zero resistance, zero uncertainty on AD converter input) with realistic (noisy, hysteresic, etc.) AD converter output and a \$3½\$ -digit display. Often when we ...
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3answers
265 views

How can I run a 6.5V-100V power meter on 5V?

I have an eBay power meter (V/A/W/Wh) that is specced between DC 6.5V and 100V. It's wired with a 75mV 100A shunt, like this: If I wanted to run the thing at 5 volts what would be the easiest way? ...
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1answer
87 views

Changing the full scale deflection of an analogue volt meter

I've bought an old pocket style (think of an old pocket watch) analogue volt meter and the full scale reading is 6V. I would like to change this to 3V, however I have opened it up and there is no (...
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0answers
35 views

LCD Counter and Hour Meter

In an electronic board I've found an LCD Counter and Hour Meter. Here's the technical information. https://docs-emea.rs-online.com/webdocs/001a/0900766b8001abd9.pdf Since it's very expensive, I ...
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0answers
66 views

Acquire a “TIC” signal from a power meter

I'm trying to acquire the tic signal of a french power meter. From the datasheet available here of the TIC signal we can find out that the signal is (page 7/38): 6 Vrms +/- 10% at 50 kHz It comes ...
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1answer
79 views

Considering analog meters as displays, which would be more versatile - voltmeters or ammeters?

Note: I'm here to see if there's an objective reason to choose one type over the other. I've got some projects in mind that would use a microcontroller to drive one or more analog meters as displays, ...
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2answers
237 views

VuMeter using LM3915 not working properly

I built a simple Vu Meter on a breadboard using the LM3915 IC following a tutorial found on the web, all seems to works fine and the final result is something like this: The only difference is that, ...
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2answers
129 views

Can any meter be PT connected?

I have an EE background, but am new to metering hardware. Looking at metering equipment for high voltage measurements (up to 6.6 kV), it seems most only go up to 480 V, even when classified as ...
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1answer
411 views

Which one is better to build lux meter, either LDR or photodiode?

I want to add the lux meter to my application. My controller works with 3.3V and ADC max reading voltage is 1.2Vref. I tried with LDR but I'm not able to get accurate values and the values also not ...
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3answers
615 views

Why doesn't commercial LCR meters' band start from very low frequencies?

I'm wondering why I can't find an LCR meter with frequency band that starts for example from 1 Hz. Is there some specific reason? EDIT: My question comes from the need to measure the impedance of a ...
3
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1answer
65 views

Home-made impedance meter: what's the difference between voltage divider and active filter methods

I'm dealing with the measurement of impedance sweeping the frequency from 0,1Hz to 100KHz. On the web I found many methods but the most quoted seems to be the one which uses an operation amplifier in ...
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1answer
117 views

What does the 20-80A rating on an energy meter mean?

On the energy meter nameplate is a current rating 20-80A, which I can assume has something to do with max current. I'm particularly interested in the "20" part, though. What does this rating mean? I ...
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1answer
316 views

What is the correct shunt size for the following ammeter and configuration?

I have the following ammeter: https://www.aliexpress.com/item/Red-led-Display-Color-0-56-Digital-Ammeter-DC-0-100A-4-wires-3-digit-car/1301822575.html The seller recommends 75mV 100A shunt be placed ...
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2answers
1k views

Ammeter show half of the real current draw [closed]

I have a couple of ammeters from China, they have 2 connectors: Con 1: Yellow voltage sense, Black and Red to power the ammeter. Con 2: Thick Red and black for current sense. They are designed to ...
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2answers
35 views

Ammeter ideal for testing, leaving on work bench for long periods [closed]

I am currently working on my first li-poly power supply, and I am testing Texas instruments BQ21040 PMIC. The device has three charging phases that I need to monitor to do some troubleshooting. I ...
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0answers
330 views

How much maximum electricity bill (units) can be generated on 2 KW connection?

I have got a bill of approx 14000 Units (50000 INR) for a month on 2kW connection. As per my analysis and understanding, it can't be more than 2 * 24 HRs * 30 Days = 1440. I think electricity meter ...
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1answer
113 views

Help me identify a component

I'm trying to identify a component which I'm not entirely sure what it is. Here's an image: The component I'm asking about is circled in red. The product is a reader + transmitter for water ...
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1answer
64 views

way to display the data from a multi function meter [closed]

I have a multi function meter and i want to collect the data and display it. My idea was to create a api for serial communication?? will the idea work or is there any other better way?? the meter uses ...
0
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1answer
124 views

Old analog wattmeter 2 terminals

I got this old wattmeter with only 2 terminals in the back. It says 60 mV, which I haven't seen in similar ones. How is it supposed to be connected to measure kW?
33
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2answers
3k views

Why this small cut in Ampere meter shunt?

I have seen lot of ampere meter shunt like this. What is the reason for this small cut?
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1answer
190 views

How does the lead polarity work on a D'Arsonval galvanometer?

Following an illustration of D'Arsonval movement such as the following... I notice that the N polarized part of the coil is connected to the positive lead and the S polarized part of the coil is ...
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2answers
155 views

Questions about clamp meters

Are clamp meters as accurate as multimeters? Could I replace a multimeter with a clamp meter? What can clamp meters do that multimeters can't? What can multimeters do that clamp meters cant?
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0answers
278 views

Poor man's capacitance meter with range control

I'm interested in making a capacitance meter with on-hand parts. Rather than connecting a bare microcontroller I'm inclined on using my Arduino Mega, since it has a built-in power supply and USB ...
1
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1answer
307 views

How to “fake” a megawattmeter

I have a vintage megawattmeter. It is able to indicate values from -1 to 7 MW. I wish to be able to provoke it to display any value I want, preferably without actually generating megawatts of power. ...
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2answers
377 views

Changing the offset and span on an analog voltmeter

I have an analog meter. It belongs on an electric e-bike.. The default reading is about 88v-84v DC high side and 63v DC low side. It has a resistor and diode on one side then two diodes in series on ...
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2answers
391 views

Is there any analog meter with the needle capable of a full revolution?

Is there any analog meter with the needle capable of a full revolution? I have always seen only instruments where the needle can rotate only a fraction of 360 degrees, for example in the following ...
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3answers
1k views

What is the role of shunt in a Power Meter?

I just got a PZEM-051 Power meter and I can see that in order to measure the power, one needs a shunt. At least that's what I can see from different YouTube videos and I was wondering why would I need ...
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2answers
77 views

Digital insulation meter measurement limits

A Meggar digital insulation meter user manual warns: "When using 500 V measurement to measure resistance less than 1.5 MΩ or 1000 V to measure resistance less than 5 MΩ, measurement time must not ...
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2answers
120 views

Need help interpreting a Energy Meter datasheet

I am reading this datasheet for an energy meter, to start understanding how this market works. A friend of mine wants to make a test in a small office building to see if it pays having one of these ...
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1answer
208 views

PCIM176J panel meter

I scored a couple of panel meters stamped PCIM 176J. Anyone have a datasheet for this thing? Google found nothing.
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5answers
312 views

inconsistent electricity meter readings

I have the electricity meter pictured. When I attach various devices I get readings (amps, volts, watts) that are proportional. Expected values are a few percentage points off from the readings. ...
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3answers
11k views

Building a pH meter circuit - is it feasible?

Let's say I have a budget of $15-20 to build a pH meter. I will then read the analog values from a microcontroller or such, but I want to first focus on somehow getting a reliable pH value on a ...
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2answers
148 views

Voltmeter vu-meter dynamo

To start, I have no experience with electronics except what I've been googling the past week. What I'm having issues with is finding a way to make a voltmeter that functions like an led vu-meter would....
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3answers
313 views

Using IR thermometer for measuring component temperature

I'm trying to measure the temperature of various steel components being heated using power frequency induction heater. The IR meter being used can be set for emmissivity value of 0.1 to 1.0. For the ...
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1answer
2k views

ACS 712 Current Sensor Calibration problem [closed]

I have a similar circuit to: http://henrysbench.capnfatz.com/henrys-bench/arduino-current-measurements/the-acs712-current-sensor-with-an-arduino/ During my initial test it was calibrated just fine. ...
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2answers
191 views

Induction meter, finding standard reading

If I have the time it takes an induction meters disc to complete one revolution, then how can I work out the power in watts ?, I feel like i'm missing some other parameter that is needed I basically ...
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1answer
2k views

Energy Measurement in 3 phase ac split into 3 lines

I have observed that residential buildings receive 3 phase supply, even though almost all appliances are single phase input type. The phases are split into three separate lines and loads are evenly ...
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1answer
404 views

Bi-directional energy meter

I have a question regarding reading import and export energy from an electricity meter, the system has a solar array fixed allowing power to be exported to the energy grid when there is excess power. ...
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1answer
88 views

AGC which tells you what gain its at?

I am looking for an AGC (Automatic Gain Control) which outputs not only the normal output but also another output which tells you what gain it is using. I need this for an automatic voltage meter I am ...
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0answers
876 views

CT (current Transformer protection)

I try to read some value from CT. Everything is alright but sometimes I read some really high value on my arduino pin. I was looking some information about the CT protection. People talked about diode ...
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2answers
925 views

RF power meter circuit

I want to setup a radio transmitter and reciever a few centimeters apart and measure the signal strength i get. There will be a filter in between which absorbs particles and the idea is that i want ...
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2answers
1k views

Changing analogue ammeter scale from 1A to 1mA

How can I change analogue panel ammeter for metering 1A DC scale to 1mA DC ? As far as I know, you can use shunt resistor for doing this other way around, but this doesn't help much. Thank you EDIT:...
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1answer
216 views

arduino current

I want to start learning EE with Arduino so as a project I decided to build an Ohmmeter and measure a (specific) resistance that should be about 100 KΩ ±50KΩ. In order to probe for that resistance I ...