I have enjoyed my Pokit meter, and I'm looking forward to the PokitPro that is on the way. However, I recently had an issue that has me puzzled. Last night, rather than move a 20 kg transformer to my bench meter, I took the Pokit to the transformer to measure the winding resistance. The winding 'measured' at 4.2 k_ohm, which really had me concerned. I then got a 9 volt battery, put the Pokit into DC current measurement, and measured 49 mA. This would match up with the suppliers note of the winding having 180 ohms DC resistance. The meter is measuring regular resistors with no issues, but now and then I do need to check transformer windings.
To dig in further, I got out two other meters, my Cold War era TS505, which measured 180 ohms, and a Greenlee (obviously made by someone else for the Greenlee name). The Greenlee saw the winding as open, until I put the meter into continuity mode. In continuity, the winding measured at 180 ohms.
Does this have to do with the winding being very inductively reactive combined with use of an autoranging meter? Does the outgoing test voltage applied to the resistor shift as a meter hunts for the right range? The TS-505 is too simple for autoranging, and there is no autoranging with the current measurements. I'm tempted to get out my 1970s Heathkit autoranging digital meter to see what it sees.
Sorry for the long ramble, but I'm looking for my own education to understand my instruments and where I should or should not use them.
By the way, if any of you conduct similar measurements, you might want to consider a protection circuit of two zeners in head-to-head to short a voltage pulse when disconnecting the load. I'm lucky I didn't fry my Pokit when I was making current measurements. This winding stored enough energy to make my finger tingle for a while when removing the connector to end the measurement.
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