Problem-Harbor Freight test meter

I thought this might come in handy for some. The harbor freight meters can be calibrated to insure accurate readings. You will need a voltage reference or a good known accurate meter to set it with.
Open up the back cover and this is what you will find. Turning the trim pot clockwise to read more voltage and turning counter clockwise reads less voltage. Most of the meters I have had where with in .01v of being write. But I have had one meter that was .03v out. Now that there calibrated they all read dead on, besides maybe when they go through a temperature change. I did notice that these meters will read differently with temperature changes. Still close enough for battery measurements though. At what ever temp you calibrate it at, will be where it is most accurate.

Thanks for that!


It should be 1.221 V. Current x Resistance = Voltage

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