Why and when to use 1X probe if 10X is superior?

[doncarlosalbatros]

Hello,

The probe compensation is possible only when the scope probe is set for 10X.
If so why or why to use 1X setting at all?
In what circumstances it is superior to 10X setting?

 

[FvM]

The question seems to involve a wrong assumption. Missing compensation is no drawback of 1:1 probes. They simply don't require it.

The main purpose of passive 1:1 probes is low level + low bandwidth measurements where the lower probe bandwidth and higher input capacitance doesn't matter and you want to improve the signal-to-noise ratio. Read the specification of your probes.

 

[doncarlosalbatros]

The question seems to involve a wrong assumption. Missing compensation is no drawback of 1:1 probes. They simply don't require it.

The main purpose of passive 1:1 probes is low level + low bandwidth measurements where the lower probe bandwidth and higher input capacitance doesn't matter and you want to improve the signal-to-noise ratio. Read the specification of your probes.

Thanks I see that at low frequencies the compensation might not be required. But why signal to noise ratio is higher for 1X setting? Would a 1:10 resistive voltage divider introduce noise at 10X setting?

 

[FvM]

Would a 1:10 resistive voltage divider introduce noise at 10X setting?

May be, but surely the input amplifier does.

 

[barry]

You would also use a 1:1 input if you were connecting a 50-ohm signal.

 

[doncarlosalbatros]

You would also use a 1:1 input if you were connecting a 50-ohm signal.

Why is that? Thanks

 

[barry]

Why is that? Thanks

Because you don't want to connect a 1Meg termination to a 50 ohm source.

 

[doncarlosalbatros]

Because you don't want to connect a 1Meg termination to a 50 ohm source.

Im bit confused since you wrote "You would also use a 1:1 input if you were connecting a 50-ohm signal."

And then you wrote " You don't want to connect a 1Meg termination to a 50 ohm source."

1:! means 1Meg termination(scope input impedance at 1X) isnt it?

 

[barry]

means 1Meg termination(scope input impedance at 1X) isnt it?

Not if you set your scope input impedance for 50 ohms. But this is a specific case. I think we've answered the question of why you'd use 1:1 probe.