How to avoid capacitive loading when using my osciloscope

[michalism]

Hi all.

I'm trying to find a way to ensure that I am not adding a capacitive load to a component when probing around with my osciloscope. You can refer to an older post of mine, where I fried an IC trying to figure out a problem:
https://www.eevblog.com/forum/repair/ksger-t12-mini-soldering-station-doa/msg2459682/#msg2459682

I have tried Google and searching here in the forum, but I did not find anything on this matter.

Thank you!
Michalis

[Siwastaja]

Use x10 probe instead of x1. Those with selectable switches, glue or tape it in the x10 position. x1 is very rarely needed IMHO, and it's frustrating whenever your probe has accidentally changed to a x1 probe and your voltage values are 10 times off.

If you still have too much capacitance, the options are:

A cheap DIY "lo-z" probe
https://www.eevblog.com/forum/projects/lo-z-probe/
which trades lower HF AC impedance for higher DC resistance,

Or an expensive active probe which has a tiny FET amplifier in it.

Cases where the 10-20pF of capacitance would kill a circuit are very rare, though. It's likely you did something else which killed your soldering station. Ground loop, for example. Or shorting two adjacent pins with the tip.

[cdev]

You can make your own active (FET) probe for just a few dollars in parts

Bob Pease wrote about this.

https://easyeda.com/andyfierman/project-g2QNnljhf
http://www.introni.it/pdf/Bob%20Pease%20Lab%20Notes%20Part%208.pdf


Good to put into a hand-friendly well shielded enclosure.

[michalism]

Excellent! thank you both!