Overvolted multimeter?

Hi.  Simple question. (or maybe not) I have a digital multimeter I bought a while ago that I think I accidentally put too much voltage through. The voltmeter function on it is now broken. Whenever it's turned on, it reads "156 VDC" even though no voltage is being applied. (however, when I do apply voltage, the meter does detect it.) All other functions seem to be working correctly, but I'm bummed because the voltmeter is what I use the most. Is there any way to "reset" a multimeter? if not, is there anything I could try to fix it? Thanks in advance.

Question by tylervitale   |  last reply


Add a buzzer to a multimeter? Answered

Hello, is it possible to add a continuity check buzzer to this MAS830S mutimeter ? i would like to do like on this video but i cant find which resistor is the good one http://www.youtube.com/watch?v=ItqYUUjcwfk i don't care if the buzzer is inside or not thanks

Question by rastactivist   |  last reply


are these sufficient specs for a multimeter?

These are the specs off a multimeter im about to buy. are these enough to do electronic projects off instructables.com, fixing electronics, and etc? if not then what do i need then? thanks DC Voltage: 200mV-1000V AC Voltage: 2V-700V Temperature: 20°-1000°C Resistance: 200Ω-20MΩ DC Current: 2mA-20A AC Current: 20mA-200mA Capacitance: 2nF-20µF Frequency: 10Hz-20kHz  

Topic by leader1   |  last reply


Testing a Cheap Multimeter

It's been years since I had an expensive meter. These days, I have meters in the $5 to $20 range. Usually they're accurate enough for my purposes, but what if I want to be really certain? Is there a way without a pricey meter to test em?  Perhaps calibrate the meter by checking v  coming out of a v regultor. Would that be accurate? Perhaps the 7805 regulator which is supposed to output 5v.  y?n? M?

Topic by Toga_Dan   |  last reply


Multimeter DIY Repair?

I have a Radio Shack digital multimeter, Model 22-174. Since the 10 Amp measurement circuit is not fused I blew this circuit and that part of the meter does not work now. I like this meter and would like to know if I can DIY repair it and what I need to do. I have looked around the Internet and have not found any information including the Radio Shack site. Was looking for the wiring diagram only found a parts list. I hope that I can fix it. If I can fix it I will fuse the test leads (black lead) or work out an internal fuse for this circuit so I don't repeat my mistake. Any help would be nice. Thank you.

Question by phantom9   |  last reply


Arduino Multimeter on 1602LCD? Answered

Hi I am currently in the process of finishing the code for my Arduino controlled PSU with an LCD volt and amp meter. My question was basically, how can I get the volts and the amps to show on the LCD with 3 decimal place digits instead of 2 which i have now. Also, im having trouble putting 4 measurements all on one display- i currently have watts, amps and volts but i wanted to add resistance, however, for some reason i cant fit them all in one screen and i get weird errors when i try changing the setCursor value.  Thanks P.s here is the code I'm using (a took bits off different websites and examples-will reference them in the final sketch) #include const int numRows = 2; const int numCols = 16; LiquidCrystal lcd(12, 11, 5, 4, 3, 2); int analogInputVolts = A0; //voltinput int analogInputAmps = A1; //ampinput float vout = 0.00; float vin = 0.00; float amps = 0.00; float watts = 0.00; float ohms = 0.00; float VA = 4.970;          // Arduino 5V supply float R1 = 2995;        //  R1 in ohms float R2 = 999;        //  R2 in ohms int readAmpsADC = 0; int readVoltsADC = 0; void setup(){   Serial.begin(9600);   lcd.begin(16, 2);    pinMode(analogInputVolts, INPUT);    pinMode(analogInputAmps, INPUT);    delay(500);                    } float fmap(float x, float in_min, float in_max, float out_min, float out_max) {   return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min; } void loop() {    readVoltsADC = analogRead(analogInputVolts);    readVoltsADC = readVoltsADC + analogRead(analogInputVolts);    readVoltsADC = readVoltsADC / 2;    vout = (readVoltsADC * VA) / 1023.0;    vin = vout / (R2/(R1+R2));     delay(100);         readAmpsADC = analogRead(analogInputAmps);    readAmpsADC = readAmpsADC + analogRead(analogInputAmps);    readAmpsADC = readAmpsADC + analogRead(analogInputAmps);    readAmpsADC = readAmpsADC / 3 ;      // get average of 3 readings    amps = fabs(fmap(readAmpsADC, 509.0, 699.0, 0.0, 5.0));    if (amps < 0.09) amps = 0.00;    if (amps > 5) digitalWrite(13, HIGH);    delay(100);    if (vin < 0.5) vin = 0.00;          watts = vin* amps;    ohms = vin / amps;    Serial.print("Resistance-Ohms:");    Serial.println(ohms);    if (amps = 0.00) Serial.println("Nil");          lcd.print(" ");    lcd.print("V:");    lcd.print(vin);    lcd.setCursor(1, 1);     lcd.print("A:");    lcd.print(amps);   lcd.setCursor(0, 0);      lcd.print(" ");    lcd.print("W:");    lcd.print(watts);    lcd.setCursor(7,0);       delay(400); }

Question by lightemmitingdiode   |  last reply


E-sun UT30C Multimeter?

I have a couple of multimeters that display a '1' on the screen at all times and don't measure anything anymore. Does anyone out there know how to fix this? Thanks

Question by Physatwes   |  last reply


my 35 year old analog multimeter suddenly packed up?

There is no continuity on several cylindrical parts with coloured stripes on them, transistors??. 1 Diode "D1"  does not test either. Is it possible to identify the parts I marked with red dots in the foto attached so that I can order them from somewhere in the UK. I do not know where from either. Thank you There is no continuity on a few small cylindrical parts no

Question by ulindel   |  last reply


a couple of questions

I have a greenlee multimeter and i cant get it to give a read out it just stays at 0 it was working fine then all of the sudden it will not do anything any ideas as could be wrong? resistors? does it matter which way they are connected and when i hook one to a power lead and stick a multimeter on the other side the voltage should be different right?

Topic by LoveforBlueFarms   |  last reply


have a archer kit 28-2014a cannot get resistance to work.

All resistors in r circuit are good but am not sure how selector switch works a good assembly instructions would help

Question by frankkey   |  last reply


there a way to calibrate an autoranging multimeter?

Hello community, I have a little problem with auto ranging multimeter Techman brand TM-107 the question is that I would like to calibrate and mark certain ranges wrong, I have intermediate level knowledge of electronics, the question is whether by changing parts that do not make their specific value would fix the problem or would have to make other method?

Question by jediknightgeorge   |  last reply


What multimeter should I get?

After making my first few electronics projects I've learned that I really should get I multimeter so I don't screw everything up. So I've been looking around a bit and there's a lot of choices out there and I don't really know what features I should be looking for except I do know I want to get one that can read loads up to 4 to 5 amps (or maybe even more). I only want to spend around $30-$60. I found this one on amazon http://www.amazon.com/exec/obidos/tg/detail/-/B000JQ4O2U/ref=ord_cart_shr?_encoding=UTF8&m;=AMH4W1K8OCGMX&v;=glance does this look like a good one?

Topic by cannedham160   |  last reply


Testing Tesla coil frequency with a multimeter frequency (Hz) meter?

My multimeter can measure up to 20MHz and I was wondering if I could test the resonant frequency of my Tesla coil by running it (untuned) then having the multimeter attached to an inductor a few feet away?  Would this work or would I need some kind of small circuit attached to the multimeter as well? If I could do this would it work with the primary as well?

Question by The MadScientist   |  last reply


How do I tell if my multimeter is dead?

I was trying to measure current, then voltage and - basically I had no idea what I was doing and soon everything returned zero. Opened it up, dont see the wire in the fuse anymore. It was rated 250ma 250v 5Ø 20mm. The shop I went to did not have it so I settled for a generic looking fuse rated at 250ma. The multimeter still shows 0 for all the batteries I've tried. Is it time to get a new meter or find a proper fuse?

Question by pantss   |  last reply


Autorange Brymen BM511?

I have an unusual problem. My BM511 will not auto-range and readings on VDC are odd. A 1.5v battery initially shows OL, then 00.61, 001.5 then 0002V as you manually step up through the range of the meter using the 'range' button. I suspect it has been burnt, either the input protection, bridge or scale divider. As I do not have a diagram i cannot fault find. Does anyone have a circuit diagram for the Brymen BM511 DMM. Thanks in advance. Regards, KH

Question by KeithH65   |  last reply


Radio Shack Digital Multimeter beeping?

I bought this meter last week and when turned on it does not cease beeping. I know this is not normal. Is it bad or can the beeping be stopped. I looked in the instructions a and could not find anything on this. Thanks, MV

Question by Manolo71   |  last reply


Two loss wires to solder on stereo wireless hp's, both red, which one goes where using multimeter?

Hi, I have two disconnected red wires on the left side cups that need reconnecting to the L- & 3V on the board which you can see on the image below. https://www.dropbox.com/s/pisf15rkthlnlyk/DSC02001.JPG https://www.dropbox.com/s/9e97veutva4gpaj/DSC02000.JPG https://skydrive.live.com/redir?resi...M_vkdGusRCa8oc https://skydrive.live.com/redir?resi...M_vkdGusRCa8oc My question as a multi-meter novice, how do a test to know which red wire goes to which point? Also is there any danger of overheating the board on so small solder points? Any help much appreciated

Topic by Optical10 


Adding an indicator led to a multimeter when it is on? Answered

I would like to add an indicator led because I keep leaving it on and draining the power.

Question by hkerr   |  last reply


what do these features do on a multimeter??

I went to this website to help me find a multimeter and these features were in the filter that i either dont know what they are/do or know if they are important. so can anyone tell me what these features do on a multimeter, what they are used for, and if they are important. 1. frequency 2. period 3. ratio 4. temperature 5. Vp-p 6. diode 7. continuity 8. 2/4 wire resistance 9. conductance 10. dBm 11. duty cycle 12. inductance. 13. pulse 14. TRMS 15. capacitance note: they have said that capacitance doesnt need to be a feature do to problems and i want to use a multimeter to simple to complex electronic projects like on instructables.com and robotics when i get to that level. thanks

Topic by leader1   |  last reply


Radio Shack digital multimeter issue

Model is 46 range pc interface. Got it last week, second one after the original went bust, so rs interchanged it. But this one once turned on, does not cease to beep continuously. I know this is not supposed to happen. So, how do i stop this beeping? Thanks

Topic by Manolo71   |  last reply


MultiMeter Reading Wacked? My brain wacked?

Ok so I just bought a new meter and I decided to test it out on my new circuit, but I was much surprised! The circuit is identical to this one: https://www.instructables.com/file/FSKP1NOHS18BW4T/?size=MEDIUM except for instead of 4 leds on rows 1 & 2 it has 8 leds per row.  Since I didn't want to type it all up heres the video. So all help is appreciated! Thanks!

Topic by HavocRC   |  last reply


Need help with an LED project Answered

I've almost collected all of the necessary parts to start experimenting. Just enough for simple experimentation. Though I'm curious what type of wire I'll need to find to connect everything. I'm using a breadboard. Also, I have a multimeter, is there a way I can test the voltage of the LEDs to make sure I pick the right transistor?

Question by Crucialitis   |  last reply


What's the difference between a Fluke 87III, 87IV and 87V?

The series designations are confusing me. A couple of the sites I've visited have mentioned the series V can withstand 8000V switching transients. But then, you never know when something is just marketing hype and all of the series can withstand 8000V switching transients. I ask because I'm currently studying transient phenomena (LV), and will be working my way up to HV in the future.

Question by Vorenus   |  last reply


Amp hour draw question for LED setups

Hi, I have an led setup that is drawing .39A  @12v.  I am running it with a 4.5ah alarm panel battery. My questions are: Is there a way to calculate the how long this set up will run  knowing that leds stop working when the power dips under a certain amount?  I have been running this set up for about 4 hours at a time, about once a week without issues for several years.  I always top off the battery at a 2amp setting on the charger.  It always takes less than an hour to top off after 4 hours of use.  This is probably good for the battery cause it shows that it isn't being drawn down much during it's 4 hours of use.  I then put it on a float charger for storage till the following week.   Could this be run on a smaller battery without affecting the battery life?    I would like to run the smallest and lightest set up possible while maintaining the health of the sealed battery that probably doesn't like heavy recharge cycles. What is the smallest I should go while keeping the battery healthy?  Thanks for the info. 

Topic by thewetturd   |  last reply




Resettable Fuse PPTC Polyswitch instead of normal fuse?

Hello Friends, I have basic multimeter which has 250ma 250v fuse in it.  some how due to bad test it fused due to higher amps. now I am planning to replace it with 250ma 250v Resettable Fuse or PPTC or Polyswitch. can I go for it or it may create problem? any body have tried?

Question by supertechey   |  last reply


How to build a joule thief? Answered

      I'm building a voltaic cell and a joule thief. I searched on some instructables and followed the one on youtube by MAKE:. When I hook up a 9V for a few seconds (To not burn the LED out), it works. However, a AA doesn't work. Not even a brand new one. So, I presume that I haven't wrapped the toroid around enough to create more voltage and lessen the amperage (If that's what joule thieves do)? I posted some pictures below. Also, I'm looking to buy a voltmeter, I'm around basic level and just need to measure if the joule thief is even increasing voltage (For now at least). Here are some cheap ones I'm looking at on amazon:  http://goo.gl/gVvo6P http://goo.gl/hKKtGu http://goo.gl/Q2rrKm http://goo.gl/MQZeeS http://goo.gl/if04Es Some of those have autoranging, is this to automatically find the voltage/amperage? Thanks, please reply

Question by knexpert1700   |  last reply


Powering a multimeter built into bench-top power supply?

Recently I built a bench-top power supply from an ATX power supply (Like the one from here: https://www.instructables.com/id/Convert-an-ATX-Power-Supply-Into-a-Regular-DC-Powe). It works great but I'm looking to consolidate this and my analog multimeter into one box. I'd like to know how to power the multimeter using the power supply so I don't have to worry about changing the batteries. The multimeter uses two AA batteries and a 9V, and the power supply has voltages of 12, 5, 3.3, 0, -5, and -12. Thanks for any help.

Question by ranab998   |  last reply


How to measure capacitance?

What is the most inexpensive way that I can measure capacitance? I have some photoflash capacitors that aren't marked with their capacitance. I went to radio shack, and the cheapest multimeter that measured it was around 60 dollars. Is there a cheap way that I can find out the rating of my capacitors?

Question by daa5849   |  last reply


What specifications should I look for when choosing a multimeter to buy? Answered

I am looking to buy a multimeter for general use and would like some advice and/ or recommendations of what I should buy. I would preferably like a digital multimeter with a price of under $50.

Question by UbuntuNinja   |  last reply



"Contactless Dynamo" / Wind generator showing weird multimeter readings? Answered

I am trying to replicate this, more or less, It's a setup using hard drive magnets and the coil from a relay to generate electricity.  My problem is that every configuration I have tried gives me weird negative and positive numbers(around -20  to 20, constantly changing while the magnets are spinning), and only in the hundredths of volts setting(on the multimeter, the volt, and thousands of a volt settings show nothing).  I have tried using: hdd magnets and round magnets (8 of them in a N-S-N configuration);  a relay coil, a small transformer coil, and winding my own coils 3 times.  The hand-wound coils have approx. 159 turns, 200 turn, and 250 turns, all with thin very thin enamel-coated wire, as it's my understanding that thinner wire will output more voltage.  No matter what configuration, I get the same erratic readings.  What am I doing incorrectly?

Question by chrispaccord   |  last reply


does anybody know how to make an IR frequency reader?

Does anybody know how to make an IR frequency reader by com port? or a 7-segment? or with a digital multimeter? P.S: Most likely to me with a digital multimeter.

Question by top.boy   |  last reply


Some help with Ohms and resistance? Answered

Hey guys, i know there are a lot of you guys out there that deal with electrical dealings and such, and im doing a science project, dealing with electrolysis, so i decided to compare two electrolytes to see which has a lower resistance, and to see which would be more efficient therefore. SO, the only problem is, i have no multimeter, voltmeter, or anything close to it, and i don't know anybody 'round her that does..So im asking you, could you help me with seeing the resistance of- * water (tap water) * water with Epsom Salts  * and water with Baking soda powder (either will work, but i would prefer powder, as baking soda is said to cause chlorine gas, and what not..whichever you have works) If you could take a picture of yourself using the multimeter, that would be stellar, thats all for now,  come on guys, i know you know this stuff, and i just cant figure it out, counting on you :)  

Question by fwjs28   |  last reply


Android USB OTG?

How to measure voltage at micro usb port on android with multimeter???

Question by PavleP   |  last reply


What is a good schematic for a multimeter with an attiny85v and some 7 segment leds?

I want to make a multimeter out of an attiny85v, and some 7segment leds for a 12volt power supply that I made, I would like it to measure from 0.0V to 12.0 volts, with an accuracy of .1 volts. Anyone know any good circuits? EDIT: This is what I am looking for, except the author has not included any code http://fedetft.wordpress.com/2010/10/02/digital-voltmeter-for-power-supply/

Question by Michael_Bell   |  last reply


Testing a NST with a DMM?

I have been looking for a good (and cheap) NST for a while but i dont want to risk spending too much on a NST that doesnt work. I know that my local scrap yard has a large supply of old NSTs that are either there because both or one side doesnt work, they were upgraded, or someone needed the money and/or space. i also know that they would frown upon me wiring each one up and testing each. so onto the real question: is there a way to test a NST with just a multimeter and possibly a battery (i know thats how some people test for flyback transformer pins) or if checking continuity would be enough or even another way? Just so everyone knows i have spent quite a while searching for someone using this technique but didnt find anything, also im looking for a way to know for sure if one or both sides are working.

Question by pmk222   |  last reply


Determining the amperage output of transformers?

I have two giant audio transformers that put out about 70 volts each. I want to determine what the maximum amount of current they can supply is, because they're really nice transformers, and I wouldn't want to break them by over-heating them. Is there any way to do this mathmatically? I have a multimeter that can measure ohms and voltage, but it can't measure watts, and the fuses for the ammeter are blown, and I can't replace them right now. Bear in mind that this is about as much as I know about the transformers, other than they're heavy, and that primaries are 120 volts each.

Question by tylervitale 


How to measure verry smal current (amperes) with multi meter?

Hi I'm trying to measure how much current can be generated from tomatoes. Please have a look at http://maaikedevos.blogspot.com and my question will make a lot more sence. What option should i use ( 200u, 2000u, 20m, 200m) if i use 20 on the voltage and i want to use the formula W=VxA ? It seems to me that the measuring in itselfs alters the numbers. The brightness of the LED changes. What is happening here ? How can i measure amperes ? On the picture: 1/ LED hooked up to a battery. Multimeter placed in series to measure the current. (the LED seems to light up but this is reflection) 2/ I turn the multimeter to 200m, the LED lights up very brightly. On the display: 03,8 3/ Multimeter is turned to 20m, the LED lights up. On the display: 3,29 4/ Multimeter is turned to 2000u, the LED lights up. On the display: 1197 5/ Multimeter is turned to 200u, the LED lights up but not verry strong. On the display 1  . Thanks to any one who can explain this to me in clear language. This are my first staps in elctricity-land. greetings, Maaike

Question by dr zeezucht   |  last reply


how to measure frequency in this circuit?

i want to measure the frequency of this flasher circuit but i always get a frequency close to that of the mains. I am using a wall wart. i changed some of the components to speed up the flashing but the frequency reading stayed the same. to check my multimeter i tried measuring the frequency of mains and the joule thief circuit and it looks like my multimeter is good. how should i measure the frequency in this flasher circuit?

Question by codestroy7   |  last reply


help with capacitors please? Answered

I am trying to double the output of a 1.5v battery to 3v i have setup a capacitor parallel circuit like this                --------------+ capacitor - -------------+ capacitor - ---------------                                                                                                                                  +                                                                                                                     Battery                                                                                                   -------   + Multimeter           -                                                                                                             -------    - Multimeter               -------------------------------------------------------------------------------  However i am not getting the output of 3v, i did this yesterday and had 3v but today im only getting 1.5 i tested the battery on its own and that is 1.5 so why is it that i am not getting 3?

Question by connorfrancis   |  last reply


LCD to 7 Seg or even better BCD?

The challenge: I need to change the LCD output of this chip to 7 seg and then eventually to BCD.  Personal Reason: I'm trying to make a Nixie tube Multimeter. I'm currently testing with some old 7 seg displays so that I don't worry my self with the high voltage of the Tubes, but eventually I need the output of the multimeter to be BCD so that I can use it with the drivers for the Nixie Tubes.

Question by JoeShmo1 


i was repairing a home amplifier when it "unrepaired" itself. help?

I found a samsung mm-c430 home amplifier the other day, and decided to take a stab at fixing it. i replaced a few burnt out parts and tried it out. nothing. then, while using my multimeter to check things, i noticed the main transformer wasnt putting out any voltages. this lead to more probing around a mosfet when suddenly the VFD lit up and the device appreared operational. my multimeter had shorted out two contacts and that led to the system starting up the way it should, rather than just turning on the LEDs. i turned off the device and turned it back on, and just the LEDs lit up. then i went back with my multimeter to the same spot and t started again! so i went and soldered two wires and a load (resistor) and went back to try again. the resistor burned, and the device did not power up properly. i tried again with my multimeter and nothing. i removed the wires and tried again, and still nothing. now im really confused with whats going on here. can anyone help? attached a photo. it was taken before any repairs were done, but the two points are labeled. the chip is a pwm controller, and the pin labeled is VCC

Question by zack247   |  last reply


Solar Cells? Answered

Is this a good set up for a series/parallel configuration? when I test it with a multimeter the voltage was around 2.5 v each cell produces 3v@40ma. so something is wrong here.

Question by dominick.j.pezza   |  last reply


12v DC battery amp measurement? Answered

HI, I have a 12v dc battery and I wanted to measure the amps. Can anyone show me how to hook up the multimeter? Thanks

Question by amantux   |  last reply


How do I determine the scan matrix of my piano keyboard?

Hi, I am trying to convert my old shitty keyboard into a midi controller by following the instructable by Evan Kale; https://www.instructables.com/id/Add-MIDI-port-to-Keyboard/ but when connecting two wires of the ribbon to my multimeter, which is set to continuity mode (as seen at 1:30 of the video in link above), there is no response from the multimeter when pressing the keys in order to determine the scan matrix. Am I doing something wrong? Please help!!!

Question by hbade   |  last reply


Tesla coil, secondary?

What kind of multimeter would measure the output in volts and the frequency of my secondary. It totalling in height is 22.7inch with a 3.5168inch diameter. Primary applied voltage 13.66kv with a distance of .5in between primary coil and secondary

Question by wiccakingkamui   |  last reply


Eurorack UB1222FX-PRO troubleshooting help (power supply)?

I got a Eurorack UB1222FX-PRO sound mixer/whatever from my school a while ago. It was broken and wouldn't turn on so that's why I got it. I'm not exactly sure whats wrong with it but im pretty darn sure that something is up with the power supply as nothing on the board is even powering on. But there is some power coming out of it to the main board but im not sure if its just not enough power or what. I know my chances of anyone on here knowing whats up are pretty slim but I don't have anything else left to do, and it doesn't hurt to ask. Im not exactly sure what to be testing or how to test things for that matter. It doesn't look like anything is wrong with it. I have a digital multimeter but it doesn't have many settings and im not sure if im testing parts on the right setting. sometimes i get readings and sometimes i dont. Anyway, if someone could maybe guide me through a troubleshooting process that could possible narrow the problem down that would be great. if not ill just scrap it and steal all the parts out of it.  If you need more pictures or more information i'd be more than happy to provide them.  EDIT: I doubt this will help any but here is the manual: http://www.behringer.com/assets/UB1222FX-PRO_M_EN.pdf

Question by knex.gun.builder   |  last reply


Question about low voltage power supplies

I have several wall plug power supplies. The voltage on one says 12v 300ma but on my multimeter im getting 17 volts. Why is it 17v and not 12v?

Topic by Rob K   |  last reply