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Low frequency/DC oscilloscope probes

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I've been reading up a bit on probe design and understanding why oscilloscope probes are designed the way they are. Mostly this seems to be about working well at RF frequencies and higher.

But if I am interested in sampling low frequency signals, say in the 10's to 1000's of Hz on a DSO, is there any reason to continue using a specially constructed probe? Suppose I just used a pair of separate leads like on a multimeter, and perhaps put a 100k resistor across the input to reduce noise picked up by the leads? This would be for use above the sampling frequency of a typical multimeter, but much lower than traditional oscilloscope territory.

It's often much easier to connect a separate pair of test leads to a circuit than an oscilloscope probe with a short ground clip. Are there any downsides to this that I have not foreseen?

As long as the DC voltages are low enough to be safe for the oscilloscope, there is no reason why you can't directly connect the oscilloscope to the circuit under test without any probe for 1KHz and lower.

It is exactly what the x1 setting on an oscilloscope probe is doing anyway.


I use x10 all the time, unless i have a reason to need x1.

With x10 your scope front-end is protected a bit more.

For example, if you were probing a circuit and got 1000V of back emf from a relay because the diode was open.
If it's on x10 then it's only 100V to the scope but if it's on x1 then it's the full 1000V into the input channel.

The rigol, for example, is rated to 300VRMS max on the front-end.

I see. So instead of making a test lead to BNC adapter, I could make a probe to banana socket adapter. My adapter would have two pins to clip the oscilloscope probe on to, connected to banana sockets for the test leads.

Or buy some adapters:


But Psi's warnings are correct. One mistake in a circuit with inductors, and your scope is dead.  Using a X10/X1 probe has the advantage that at least you can start at x10 and check that nothing bad is happening.

You could add your own protection like back to back zeners across the scope input and an extra 10K HV resistor going to the test circuit. It will reduce all the voltages to the scope by 1%.


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