Oscilloscope Probe Question

[TheOne]

I just buy a oscilloscope finally, Since I am a noob in this area I need to know something!

I buy a USB to PC oscilloscope (DSO-2150 USB), on the front where you connect the probe its say max input voltage 35V

On the probe in mode X1, its say X1 <200V DC/AC and X10 < 600V DC/AC

Now my question, If i want to probe a coil, if the coil have peak of 400V, If I use the probe in mode X10 its fine? Why the warning 35V where you plug the probe?

Sorry for my stupid question but since I know nothing about it I prefer ask before broking my new probe

Thank you

[gyulasun]

Hi,

If there is a 35V limit at the input, and you use x1  (1:1)  probe, then you cannot measure higher than 35V voltage with it.

If you use x10  (10:1) probe, then you cannot measure higher than 350V voltage with it.  If you do, then you will exceed the 35V input limit and damage may occur in the input circuits of your PC scope.

The probe has its own spec what you quoted, it can handle <200V DC/AC at x1 and  <600V DC/AC in itself, without any damage.  But your stronger limit is the PC scope input limit of  35V.

Gyula

[TheOne]

Ok, So if I need to measure higher voltage (>350V) I need to buy a new probe that support to be able to support higher voltage right?

Thank you, I begin to understand how it work.

[gyulasun]

Yes,  you need to buy another probe for measuring higher than 350V voltages.
I have just searched for your scope on the net and found this:
http://www.darkwire.com.au/html/dso-2150_usb.html

So they recommend an even safer approach by showing measurement ranges with x100 and x1000 probes:

5. Voltage Range:
- 10mV ~ 5V/div @ x1 probe
- 100mV ~ 50V/div @ x10 probe
- 1V ~ 500V/div @ x100 probe
- 10V ~ 5000V/div @ x1000 probe


So there exists a x100 and and x1000 probe for this scope but not as a standard supply.  You will probably find such probes at the DSO-2150 manufacturer home pages as recomendations or maybe even in the description you received with the scope.

Gyula

[z_p_e]

Or just build yourself a little box that interfaces between your probe and the scope and save yourself tons of $.

When dealing with high voltages and coils, it is not that critical to have precise attenuation. You can thus use 5% resistors. You're just building a voltage divider in the box, and you could use a rotary switch to vary the attenuation.