Questions tagged [meter]

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Why could a cheap electricity consumption meter break on modified square wave inverter?

I have a number of cheap electricity consumption meters of which I used one on a modified square wave inverter I bought. They cost less than 15 EUR per piece so most likely they don't have much ...
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1 vote
2 answers
95 views

Identification - 3-pin 3.3V serial port?

I'm trying to identify this port and read data off it. It's 1cm across, including a small square on the lower left. 3 pins, leftmost near square seems to be GND and rightmost reads 3.3V+ w. respect ...
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0 votes
0 answers
45 views

Reading data off a watt-meter comm. port

I have a no-brand Watt meter with an unlabelled 3-pin port at the side, presumably for reading the data off it. Pic: https://imgur.com/a/IuxEUh3 Ebay listing: https://www.ebay.com/itm/154741876757 ...
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8 votes
1 answer
860 views

Restoring and operating a temperature gauge from the Soviet space shuttle Buran

After the Soviet Buran (БУРАН) program was suspended in the late 1980s, the Buran space shuttle was housed in a hangar at Baikonur. That hanger unfortunately collapsed due to structural failure in ...
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0 votes
2 answers
72 views

Why do we need an isolated USB to TTL converter cable for communication between the desktop CPU and the target? [closed]

We can use non-isolated USB to TTL cable in between battery operated devices, ut when we are dealing with AC devices like communication between desktop CPU and electric meter (embedded MCU), we need ...
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0 votes
1 answer
122 views

How do older-style meters still in use keep their clocks synced?

How accurate must the real time clock of an electricity meter be? Apologies if this is more a legal question than an electrical one. I am particularly interested in Western Europe but also interested ...
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1 vote
0 answers
61 views

How to test if a domestic 3 phase power company meter is reading wrong?

BACKGROUND: Domestic 3 phase 220VAC supply in Thailand. Power company meter is 4 wire GE 3 phase 15A/45A. Massive power bills when mains breakers were turned off (back in home country for 9 months ...
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-1 votes
1 answer
51 views

Access meter readings remotely

I am not an expert on interfaces and communication protocols and I am trying to get data from several meters to read it remotely. The meters have an M-Bus interface to a Data-Logger. The Data-Logger ...
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0 votes
0 answers
56 views

Increase voltage level to frequency meter

I have a frequency meter that requires a minimum signal voltage of 10VDC to read the frequency. My output level is only about 2.5-3VDC. What is the easiest way I can amplify my signal voltage to ...
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0 votes
1 answer
95 views

Help understand the role of an inductor and its value (educated guess)

This circuit is a part of a field strength meter circuit in an old magazine, the value of inductor J1 is unknown (due to a print error in the magazine.) The circuit works like this: With S1 open and ...
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  • 487
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1 answer
53 views

How to calculate energy added to grid using active and reactive power?

I have recently installed solar system that adds energy to the grid. My utility company has installed bi-directional meter at my place to record energy consumed as well as energy added to the grid. ...
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0 votes
2 answers
121 views

How does power factor show itself in this data from sensor readings?

Suppose I have a single phase system and I have a sensor attached to to measure both voltage and current. The sensor samples for 50 kHz and the data is saved to a file. When we then graph out the file ...
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20 votes
5 answers
3k views

Why is this meter giving different readings depending on its orientation?

My newly-restored (re-capped) 1950s vacuum tube voltmeter is now operational...but there's one further issue. The meter gives correct readings when lying on its back, but when oriented vertically- as ...
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3 votes
1 answer
271 views

Clamp meter readings

I have a Uni-t UT210e clamp meter. I noticed that when measuring AC current, the reading varies if I move the wire inside the clamp. The measured value displayed on the meter is higher when the wire ...
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  • 293
0 votes
1 answer
64 views

Need diagnostic tips for ancient Sanwa YX-360TRe

I need to fix my sentimental value Sanwa YX-360TRe analog meter. It was bought in 1995, slightly used. It can correctly give DC voltage reading. The problem is, it cannot zero-ohm adjust in all ranges,...
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0 votes
0 answers
130 views

How to correctly bond two 200 amp main panels on a 400 amp service

I currently have a 200 amp service with a single 200 amp meter. That meter feeds a 200 amp main panel on the other side of the wall that the meter is mounted to (think standard residential ...
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0 votes
1 answer
22 views

When using a Primera-Line Wattage and Current Meter, is it showing AC or DC measurements?

I am new to the electrical engineering stuff and am looking for some guidance. I'm going to be designing a off-grid power system for some devices. So I will need to get the power measurements from ...
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27 votes
2 answers
2k views

What do the line-and-circle symbols mean on these electric meters?

I was looking at an electrical installation and came across unfamiliar symbols on the front of a pair of meters. These are from three-phase 240v meters running on a timed system. One each for peak/off-...
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1 vote
0 answers
324 views

Sound level meter using a microphone with ADC

I'm working with STM32F4, MAX4466 amplifier and a condenser microphone. In other words, Adafruit 1063. I want to get the sound level in dB unit. I know: Microphone sensitivity: 0.0063096 V/Pa ...
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1 vote
3 answers
216 views

Drive a VU meter negative from "0dB" to show compression with VCA compressor

I have a simple VCA compressor based around the THAT 2180 VCA. http://www.thatcorp.com/datashts/dn115.pdf I would like to use a standard "VU meter" to indicate compression, but work in "...
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1 vote
2 answers
65 views

Add second sensing circuit to already wired reed switch

In my house I have a mechanical water meter with a 2 wire reed switch that sends a pulse every 10 liters to (I suppose) an electronic meter to witch I don't have access. I'd like to connect a circuit ...
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0 votes
0 answers
93 views

Where are the sensors of the EMF/RF meter on the circuit board?

In the attached photo you can see the PCB of a simple EMF/RF meter. This meter shows, at the same time, the values of the electric field, magnetic field, and power density (see small illustration on ...
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0 votes
1 answer
509 views

Energy meter neutral current measurement

I was reviewing an energy meter specification and I came across neutral current measurement. What is the importance of neutral current measurement in an energy meter for three phase power supply? I ...
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  • 1
0 votes
2 answers
64 views

How do moving iron meters work on AC current? [duplicate]

I read on the internet that an iron vane is attracted to a coil and the vanr is attached to a pointer. Thus we get the reading. The article also said that we can measure both AC and DC using it. How ...
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1 vote
0 answers
158 views

What is 5th Jaw?

I just purchased this meter box and need to make sure it will work fine as a standard 240 volt residential meter. I noticed it says 5th Jaw in the title. What is ...
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0 votes
1 answer
112 views

What current transformer do I need?

I have a Prime Instruments model 60-579 watt meter for a gas generator. It has a scale of 0 to 3750 watts and is marked 125 volts. So its for a 30 amp circuit. I have searched extensively for the ...
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1 vote
2 answers
181 views

Smart meters setup

I want to monitor my exported solar energy. The solar inverter (L1+N) is already connected to my mains power meter (grid) through a smart meter (SDM630), which in return, transmit RS485 data back to ...
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0 votes
2 answers
61 views

Low amplitude curent measurement [closed]

Can someone from their experience share part number for equipment for low current measurement. The current to be measured is less than 6nA. I am aware that I can connect a resistor and by measuring ...
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0 votes
1 answer
251 views

Power factor down after solar connection

We installed solar plant in factory. After that power factor goes down to 0.16. Normally it never goes below 0.85 in history even if we keep APFC off. We always maintained it to 0.99. Note - Main ...
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1 vote
2 answers
444 views

2-wire vs. 3-wire watt-hour meter?

A kWh meter (electromechanical induction meter) is installed in front of each room in our apartment to measure the electricity usage of each room. Each room has its own breaker box to set up the 110-V ...
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0 votes
0 answers
34 views

Is there a reliable way to read an in-circuit capacitor? [duplicate]

Is there a reliable way to read an in-circuit capacitor? I have a PCB-type ESR meter with a zero-force insertion socket that works for components, but do not have a meter that was designed to read ...
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  • 125
1 vote
0 answers
124 views

Will a lower resistance potentiometer improve a panel meter scale reading?

I have an analogue tacho/RPM panel meter on an auto distributor tester, c1950s. This is not the original meter. It has two scales 0 - 6000 rpm and 0 - 1000 rpm, with a toggle switch between the two. ...
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2 votes
5 answers
521 views

Can I connect this meter to 220vac?

Can I connect this analog meter directly to 220VAC without any additional components? And what is the meaning of writing on the right?
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10 votes
3 answers
1k views

In below picture, is ammeter AC or DC? Is there direction for connection with load in series? If so what if I connect in wrong direction?

This is front view of analog ammeter. There are 2 terminals with nut and bolt behind it but nothing marked neither plus nor minus.
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0 votes
1 answer
119 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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1 vote
2 answers
263 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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0 votes
0 answers
113 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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0 votes
4 answers
883 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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0 votes
2 answers
1k 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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7 votes
1 answer
371 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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1 vote
2 answers
86 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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0 votes
3 answers
762 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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  • 363
0 votes
1 answer
334 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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0 votes
0 answers
38 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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0 votes
0 answers
107 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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1 vote
1 answer
119 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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-2 votes
2 answers
760 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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2 votes
2 answers
159 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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  • 125
-1 votes
1 answer
1k 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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4 votes
3 answers
860 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 ...
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