Converting high Z meter to low

[ksat44]

Just wondering if there might be a simple hack to convert a high impedance clamp meter I have to go low in order to get rid of the ghosts and phantoms ... I love my meter, but it doesn't offer that newfangled feature the current crop have.

[bdunham7]

https://www.fluke.com/en-us/product/accessories/adapters/fluke-sv225

To get the low Lo-Z you basically connect a PTC thermistor and a resistor in series across your inputs.  You might use a YS4020 PTC (or two in series) plus a 1K surge-rated resistor like the OX102KE.

https://au.mouser.com/datasheet/2/18/amphenoladvancedsensors_YS4020-1157120.pdf

https://au.mouser.com/datasheet/2/303/res_ox_oy-3082554.pdf

[ksat44]

Can always count on good, old Fluke to sell something worth $10 for over $100+.

Thanks for the reply.

[coppercone2]

its because of the enclosure being good / sealed / tested.

I  think a fair price would be like 60$

It does need to go through testing. That makes it worth while. But the low price components makes it too expensive.

[ksat44]

This might be an overly simplistic, but would something like an incandescent light bulb connected between the meter input leads take care of this problem?

[bdunham7]

This might be an overly simplistic, but would something like an incandescent light bulb connected between the meter input leads take care of this problem?

Sort of, but it will only work properly at one voltage and the parameters will be different, much lower on resistance with even the smallest of bulbs.

[ksat44]

I'm not looking to totally eliminate the ghost voltages, just reduce them to levels that when I see them I know what they are. I just plan on doing this on in a residential wiring setting, so seeing something like 17 Volts instead of 100 would still be useful to me. From what I've heard, most typical dual impedance DMMs operate much the same way, though I've never used one personally.

When taking measurements working in the low Z mode. I wouldn't be using the bulb when taking resistance measurements, if that's what you were referring to.

[bdunham7]

What I meant was that 1) you'd have to use bulb suitable for the voltage you are measuring--a 120V bulb will pop if you use it on a 240 or 480V circuit and 2) the bulb will have a lower resistance than a typical Lo-Z meter which (for Fluke) is usually about 3k-ohms cold and a lot more hot.  If you understand all that, then yes a bulb is a possible solution.  But if you're making something anyway, a resistor and a PTC or two aren't all that expensive.