Input Impedence

[jj5]

The manual for my scope says that its input impedance is 1 MΩ. I hooked channel 1 on my scope



up to my digital multimeter



and the measured resistance was 0.7767 MΩ.

Does that mean that the other 0.2233 MΩ is reactance?

[bdunham7]

Hmmm, no, the 1M should be the DC resistance.  Can you try changing the vertical scale for CH1 to at least 5V/div?

[Bud]

One Chinese made gizmo is measured using another Cinese made gizmo. Nothing can go wrong.
You should start with checking accuracy of your Owon.

[jj5]

Hmmm, no, the 1M should be the DC resistance.  Can you try changing the vertical scale for CH1 to at least 5V/div?

Ah, so the problem seems to be that the BNC to banana adapter that I was using had a 1.5 MΩ resistance across it. I used a different cable (BNC to banana) and the measured resistance is now 1 MΩ as expected. Thanks.

[shapirus]

One Chinese made gizmo is measured using another Cinese made gizmo. Nothing can go wrong.
You should start with checking accuracy of your Owon.

these chinese gizmos tend to be surprisingly accurate and rarely the place to start troubleshooting at these days.

[BillyO]

these chinese gizmos tend to be surprisingly accurate and rarely the place to start troubleshooting at these days.

Indeed.

I have two trombones here, both from China.  One is $200 and is what you'd expect.  The other is $6000 and is a full out professional instrument of the finest quality.  Seems painting everything from China with the same brush is a little silly.

[coppercone2]

that adapter is shit and you should throw it away. You can try cleaning it but be careful dipping those in iso, I had them warp from even 50% iso dip.

I just measured 3, one from 1950 or 60, and 2 from the last 10 years. They all read open circuit.

SO it does seem like a chinese gizmo was the problem... at least I feel better for buying pomona from a supplier .

[jj5]

that adapter is shit and you should throw it away.

Yeah, I binned it.

[jj5]

For those bringing China into it, let's not forget How it Works.

[BeBuLamar]

these chinese gizmos tend to be surprisingly accurate and rarely the place to start troubleshooting at these days.

Indeed.

I have two trombones here, both from China.  One is $200 and is what you'd expect.  The other is $6000 and is a full out professional instrument of the finest quality.  Seems painting everything from China with the same brush is a little silly.

Yes I agree with you. Chinese made products ranging from the best to the worst so a Chinese made gizmo doesn't mean anything.