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I'm trying, for teaching purpose, to study the behaviour of a bridge rectifier.

When I've simulated it with Multisim, all has work as expected:

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I built a real circuit with a function generator and an oscilloscope but in this case I can't obtain the same (right) results:

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I don't understand where I'm wrong.

Any idea?

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  • \$\begingroup\$ The voltage is too small in comparison too the diodes voltages, 2.8 V versus 0.7 V. Try it with about 12 V input. \$\endgroup\$
    – Uwe
    May 5, 2022 at 9:30

1 Answer 1

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It is likely that your function generator output and oscilloscope probe are both referenced to ground. Connecting the probe across R1 effectively shorts one end of it to ground, and shorts across one of your rectifier diodes.

Try connecting two probes across R1, with both of their ground leads connected to circuit ground. Then use the math function on your scope to display the difference between the probe voltages.

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  • \$\begingroup\$ Thanks for your reply. I had imagined anything like this. May you explain better how connect the two probes through the same R1? \$\endgroup\$
    – M4Biz
    May 5, 2022 at 9:38
  • \$\begingroup\$ Use two oscilloscope probes. Connect the probe tips to either side of R1. Connect both of their black alligator clips to circuit ground, which should be the place where the ground lead from the function generator is also connected. On the scope, display the difference between the two probes. Try pressing that button labeled "Math" \$\endgroup\$ May 5, 2022 at 9:44

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