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A simple Multimeter
Posted: Fri Mar 22, 2019 10:54 am
by footplate1947
My Multimeter has started miss behaving. It is time for a new one. I lookthrough the aadverts and my my, What a choice.
Most seem to be designed for electronics engineers with a masters degree in science and electical eneering. All want is simple meter digitall or dial (last one was dial) that I can test a circute or battery. Recomendations please.. Most of the one I looked at I dont even understand the syimbles on the dials. I was brought up with an abercuss in the 50s
Re: A simple Multimeter
Posted: Fri Mar 22, 2019 11:04 am
by dynax
Re: A simple Multimeter
Posted: Fri Mar 22, 2019 11:06 am
by Brian
A lot will depend on what exactly you want it for and how much you're prepared to pay for one?
A simple basic digital multimeter shouldn't cost more than around £20.00 or less. Often these will not be able to read AC Current (Amps) and certainly wont give accurate DCC voltage readings.
For accurate DCC readings you would need a True reading RMS meter with a frequency response of 10KHz. Cost around £150 ish or more as a ball park.
For everyday testing - AC & DC Voltage. DC Current. Continuity (Ohms) Diode and possible Transistor testing too are about all you need, cost as I say from around £10 ish up. eBay may have even cheaper ones?
One thing I find extremely useful is for the meter when on its Continuity range to have a buzzer option/feature. Working on the layout testing for continuity it is so much easier to hear a buzz than try and read the display!!
Re: A simple Multimeter
Posted: Fri Mar 22, 2019 11:26 am
by teedoubleudee
Deffo agree with last para from Brian. Continuity buzzer is a must and not all meters have it.
If you're not in a rush plenty of cheap decent meters from China, have a look at Banggood.
Re: A simple Multimeter
Posted: Fri Mar 22, 2019 1:41 pm
by footplate1947
Sorry about being thick Terry but what do you mean by continuity... You lot must think I am daft. I can recondition a Petrol engine with my eyes closed. including bores and cranks. Just so you dont think I am tatally stupid.
Re: A simple Multimeter
Posted: Fri Mar 22, 2019 2:52 pm
by Brian
Continuity of a circuit is it being tested from one place to another to prove its a complete circuit and not showing a break or open circuit. i.e. it has continuity (or is continuous). A buzzer will sound too - assuming the meter has this option, if continuity is good.
Turn meter dial to its Ohms range (any will do) and then with the test leads touched together the meter will read 0.1 or less Ohm depending on scale used. This is checking the continuity of the meter leads. If say one lead was broken a high reading or Open circuit reading would be shown the same as when Ohms range is selected and the meter leads are apart. Open Circuit has no continuity. If the broken lead was partly broken through and at the break the two ends were just touching you may well read a high resistance on the meter but possibly not a full short reading This is called a High Resistance joint or connection.
A good meter usage test I used to get my new apprentices to do was to read the values of some resistors. I used 10, 100, 1000, 10,000 100,000 and 1 Million Ohm resistors and they had to check them and advise me which were which using the multimeter they had also set up (on its appropriate Ohm range for starers). Often the newest ones were thrown by the meter showing say 990 Ohm for a 1000 Ohm resistor
BTW. Two things that must always be done .... Always turn a meter Off after testing. If you have been using the Amps (Current) ranges replace the red lead back into the Volts/Ohm etc socket. Never leave the red lead in the Amps or milliamps socket once you've finished current testing.
Re: A simple Multimeter
Posted: Fri Mar 22, 2019 3:57 pm
by footplate1947
OK that's what I have always just called it testing the circuit. Continuity is just the correct term.
yes thats how I used to use my old meter I do understand ohms and his law. thanks for help.
I like the look of the one from Aldi and the price is nice. Have just got back from Berwick and looked in Aldi but they had sold out. But now I have better idea what I am looking for. ..........John
Re: A simple Multimeter
Posted: Fri Mar 22, 2019 9:38 pm
by footplate1947
I had look around the web and watched couple YouTube films and came up with one from China which on test was more accurate than 2 other more expensive models tested along side each other. To my amazement the one I chose was only £3.50 / £1.28 P&P from China
I did not think I would be able to buy a meter for £3.50 Beers are on me.
.............john
Re: A simple Multimeter
Posted: Fri Mar 22, 2019 9:59 pm
by RAF96
If you are thinking of using it for motor stall checks then it needs to be 10A capable on DC. You only need around 2A but 10A is the standard on meters, else they are only 200mA capable and any motor in series will probably blow the internal fuse.
Re: A simple Multimeter
Posted: Fri Mar 22, 2019 10:57 pm
by footplate1947
Thanks RAF .............. it is only for checking out my wiring on the railway or if I am repairing a loco or something. I don't work on cars these days I am 71 now and the car goes into the garage............