MoreWellie
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I decided I need a clamp meter for auto use but didn't want to spend a lot of money so I paid £40.99 for https://www.amazon.co.uk/UT210E-Current-Meters-Capacitance-Tester/dp/B00O1Q2HOQ
It is quite neat and comes with a storage bag that won't provide much physical protection but will keep it clean when I am not using it. It also came with batteries ready fitted (perhaps it had already been out to somebody else) and fairly reasonable english instruction sheet
It looks like the sort of plastic that wouldn't like being dropped on concrete so I will need to be careful where I put it down
I decided to jump in and try the DC current 2A range as that is what attracted me to this unit in the first place. The first thing I noticed, which I think will become a pain, is that each time you change the range selection to Amps or Volts the meter defaults to AC and you have to press Select to get it to DC
As with all these sorts of meters moving it about changes the reading that you get which is down to the earths magnetic field and that is even without having a cable in the thing. I tried Zeroing the meter whilst as close as possible to the cable and in the same orientation and then clamping round a battery cable with everything switched off but got strange readings working with very low current readings
I then removed the battery earth cable and setup another digital meter on current scale and ran one probe through the clamp and then completed the circuit so that I could see the current draw on both meters but still got varying results but the current I was measuring was 49ma on connection dropping to 3 or 4ma (readout from the conventional meter). The good thing was I could zero the meter whilst it was lying down with the cable already in the jaws so I didn't have to worry and moving the meter in the earths field
I did find that the UT meter readout was very close and more consistent when the current flowed in one particular direction which concerns me a bit as you need to clamp on cables in a position where you can read the display. I tested this by reversing the conventional meter probes one way round I got 49ma and 5ma on the UT meter and the other way round I got 79ma and 34ma (varying slightly but in this area) and this way round when the circuit was broken the reading stayed in the 28ma region and I have read elsewhere that spikes of current can cause the zero point to shift so maybe the spike direction is also important
I then moved to completing a circuit on a car battery with a small bulb (indicator repeater) and this time I got similar 330ma readings on both meters and it didn't matter which way round the current flowed so it looks like small current measurement is much less reliable than I had hoped but higher current circuits will be ok. I also tried the sidelights on a car which gave 3.2 amps which is reasonable when you add up the dash lights as well
I also gave a quick check on other modes
DC Voltage: It auto ranges to mv and the display tends to jump around with nothing connected so I think I may have pressed Zero without thinking about it. I then tried to measure the (old) car battery and it came up "O/L" (or similar) to indicate overload so I re-read the instructions but didn't find anything about switching ranges. By trial and error I ended up holding the Zero button for a few seconds and "AUTO" came up on the display at which point the battery came up 12.34v. My other (also cheapish) meter said 12.33v so I was happy with that (must put that battery on charge)
There are mentions of capacitance/diode/continuity/ohm tests which are all on the same dial setting and I found that pressing "Select" repeatedly changes what the meter is checking for
Capacitance says up to 20uF range so I tried a .002uF capacitor I had lying about and the meter read 1.980 nF so in the right ball park
Diode check showed the forward voltage drop across a standard diode
continuity whistled when I connected the probes
Holding the "Hold" button for a few seconds turns on the display back light
All round a useful tool but I was hoping the very low current readings would be more consistent. I will update this if I find a way to make them more accurate
It is quite neat and comes with a storage bag that won't provide much physical protection but will keep it clean when I am not using it. It also came with batteries ready fitted (perhaps it had already been out to somebody else) and fairly reasonable english instruction sheet
It looks like the sort of plastic that wouldn't like being dropped on concrete so I will need to be careful where I put it down
I decided to jump in and try the DC current 2A range as that is what attracted me to this unit in the first place. The first thing I noticed, which I think will become a pain, is that each time you change the range selection to Amps or Volts the meter defaults to AC and you have to press Select to get it to DC
As with all these sorts of meters moving it about changes the reading that you get which is down to the earths magnetic field and that is even without having a cable in the thing. I tried Zeroing the meter whilst as close as possible to the cable and in the same orientation and then clamping round a battery cable with everything switched off but got strange readings working with very low current readings
I then removed the battery earth cable and setup another digital meter on current scale and ran one probe through the clamp and then completed the circuit so that I could see the current draw on both meters but still got varying results but the current I was measuring was 49ma on connection dropping to 3 or 4ma (readout from the conventional meter). The good thing was I could zero the meter whilst it was lying down with the cable already in the jaws so I didn't have to worry and moving the meter in the earths field
I did find that the UT meter readout was very close and more consistent when the current flowed in one particular direction which concerns me a bit as you need to clamp on cables in a position where you can read the display. I tested this by reversing the conventional meter probes one way round I got 49ma and 5ma on the UT meter and the other way round I got 79ma and 34ma (varying slightly but in this area) and this way round when the circuit was broken the reading stayed in the 28ma region and I have read elsewhere that spikes of current can cause the zero point to shift so maybe the spike direction is also important
I then moved to completing a circuit on a car battery with a small bulb (indicator repeater) and this time I got similar 330ma readings on both meters and it didn't matter which way round the current flowed so it looks like small current measurement is much less reliable than I had hoped but higher current circuits will be ok. I also tried the sidelights on a car which gave 3.2 amps which is reasonable when you add up the dash lights as well
I also gave a quick check on other modes
DC Voltage: It auto ranges to mv and the display tends to jump around with nothing connected so I think I may have pressed Zero without thinking about it. I then tried to measure the (old) car battery and it came up "O/L" (or similar) to indicate overload so I re-read the instructions but didn't find anything about switching ranges. By trial and error I ended up holding the Zero button for a few seconds and "AUTO" came up on the display at which point the battery came up 12.34v. My other (also cheapish) meter said 12.33v so I was happy with that (must put that battery on charge)
There are mentions of capacitance/diode/continuity/ohm tests which are all on the same dial setting and I found that pressing "Select" repeatedly changes what the meter is checking for
Capacitance says up to 20uF range so I tried a .002uF capacitor I had lying about and the meter read 1.980 nF so in the right ball park
Diode check showed the forward voltage drop across a standard diode
continuity whistled when I connected the probes
Holding the "Hold" button for a few seconds turns on the display back light
All round a useful tool but I was hoping the very low current readings would be more consistent. I will update this if I find a way to make them more accurate
