Hello, newbie here. I always see there's a specification about the max Voltage, but not about current. I have a part of the circuit where I have 500mA, can I measure safely the voltage oscillation, with such "high current"? I don't want to cook my oscilloscope. Thank You

 

To measure current with oscilloscope you must use current probe. If you can put a small resistor to the circuit then you can measure voltage drop on this resistor and calculate current with Ohms law: I=U/R. But usually added resistance distorts real current flow in the circuit and maybe also normal functioning this circuit.

 

Oscilloscopes don't really measure current... Its a voltage probe... You'll need to shunt the circuit to measure the voltage across the shunt, ergo the current..

 

I have a part of the circuit where I have 500mA, can I measure safely the voltage oscillation, with such "high current"? I don't want to cook my oscilloscope.

Oscilloscopes don't measure current. They measure voltage and the input impedance is 1M-10M ohms to minimize circuit loading.

 

Your scope is hopefully connected by a scope probe that has a 10 : 1 input attenuation.
The input of that is in the order of m ohm,
as such the current that flows into the scope is minimal / next to zero

If it was not, and your scope took say 1 mA, then measuring a voltage in a board would be affected by the current taken by the scope probe.

look at fig 5

https://www.allaboutcircuits.com/technical-articles/an-introduction-to-oscilloscope-probes/


NOW. You can normally switch your scope inpur to be 50 ohms to ground, in this case your not using a scope probe .
if you connect that to a voltage, you will take current, V = IR

if you connect the scope to say 100 V , then you will take 20 amps into the scope.
You will see the scope is rated for a power input on the inputs, so that you don't blow the input 50 Ohms.

 

Hello,

The maximum voltage or power should be given either on the scope itself or in the manual.
The power for the 50 Ohms can also been given in dBm.



From this page: https://electronicprojectsforfun.wo...s/a-fet-buffer-amp-for-high-impedance-probes/

Bertus

 

Hello, newbie here. I always see there's a specification about the max Voltage, but not about current. I have a part of the circuit where I have 500mA, can I measure safely the voltage oscillation, with such "high current"? I don't want to cook my oscilloscope. Thank You

I have a current probe that is good to a few hundred Hz. It's an HP 428B with its own meter calibrated to 10A dc and a signal output that shows the wave. It's old but it works.