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I have a signal generator and an oscilloscope.

When I connect a plain BNC cable between them, and I generate a square wave, I see the square wave on the oscilloscope with the correct voltage.

However, I want to connect the signal generator to a breadboard, and use an oscilloscope probe to measure the voltage. If I connect the signal generator directly towards the oscilloscope (using an oscilloscope probe with banana plugs -> jumper wire -> resistor -> oscilloscope probe) and connecting grounds together, I get a much lower voltage on the oscilloscope.

I guess the problem is that I use an oscilloscope probe to 'output' the signal generator's signal.

Should I cut a BNC connector apart and directly connect banana plugs or whatever onto it?

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    \$\begingroup\$ Don't do that. Oscilloscope probes aren't just wires that lead back to the scope's BNC input. \$\endgroup\$
    – DKNguyen
    Feb 24, 2020 at 0:14
  • \$\begingroup\$ @DKNguyen so I should create a BNC cable that directly connects to the signal and the GND? \$\endgroup\$ Feb 24, 2020 at 0:16
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    \$\begingroup\$ Connect the signal generator to the breadboard. Then connect the scope probes to the breadboard too. \$\endgroup\$
    – DKNguyen
    Feb 24, 2020 at 0:18
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    \$\begingroup\$ Please draw a schematic. You mentioned a resistor, so obviously it can affect the voltage you are measuring. Is it a 10x or 1x probe, and do the scope settings match the probe settings? Is the scope input high impedance or 50 ohm terminated? The signal generator most likely has 50 ohm impedance and output voltage setting may also expect 50 ohm termination. \$\endgroup\$
    – Justme
    Feb 24, 2020 at 0:18
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    \$\begingroup\$ Also, don't cut the BNC connector. Buy a pre-made one with the clips you want. BNC cables are not straightforward to just cut into and connect something else to it. \$\endgroup\$
    – DKNguyen
    Feb 24, 2020 at 0:19

1 Answer 1

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Don't do that. Oscilloscope probes aren't just plain wires that lead back to the scope's BNC input. Connect the signal generator to the breadboard, then connect the scope probes to the breadboard too.

Don't cut the BNC connector. Buy a pre-made one with the clips you want. Being coaxial cables, BNC cables are not straightforward to just cut into and connect something else to it.

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  • \$\begingroup\$ Thanks for the answer. \$\endgroup\$ Feb 24, 2020 at 0:23

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