Multimeter Quirk - UK Vintage Radio Repair and Restoration Discussion Forum

Pete_kaye · 23rd Jul 2008, 4:41 pm

Why do I get a reading on 2000k range when I hold the ends of the probes .Am I acting as a Resistor or a Cap or is it something funny with my meter?It only reads on this range and jumps about 500 K.Anyone else noticed this?\it is one of those £5 jobs from Maplins.
The reason I noticed is that clutching a resistor alters the reading if held in one's fingers.

russell_w_b · 23rd Jul 2008, 4:46 pm

Quote:

Originally Posted by Pete_kaye

Why do I get a reading on 2000k range when I hold the ends of the probes.

Because you're measuring your body resistance from probe-to-probe. Spit on your fingers and watch it change!

Nickthedentist · 23rd Jul 2008, 6:53 pm

Russell's right, of course. The effect is only noticable on the high ohm ranges; on the lower ones, your body resistance is so high that it's insignificant.

This is how primitive lie detectors work.

Nick.

23rd Jul 2008, 4:41 pm	#1
Pete_kaye Octode Join Date: Jun 2005 Location: Sheffield, South Yorkshire, UK. Posts: 1,227	Multimeter Quirk Why do I get a reading on 2000k range when I hold the ends of the probes .Am I acting as a Resistor or a Cap or is it something funny with my meter?It only reads on this range and jumps about 500 K.Anyone else noticed this?\it is one of those £5 jobs from Maplins. The reason I noticed is that clutching a resistor alters the reading if held in one's fingers.

23rd Jul 2008, 6:53 pm	#3
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,866	Re: Multimeter Quirk Russell's right, of course. The effect is only noticable on the high ohm ranges; on the lower ones, your body resistance is so high that it's insignificant. This is how primitive lie detectors work. Nick.