Hi I have a Diode Bridge as outlined in the image below. As you can see I am getting a negative voltage on one pair of diodes instead of this voltage being flipped to positive.

Can you see anything wrong with my design or does it look like the simulator program getting it wrong?

enter image description here

Using Every Circuit Simulator on Android.

  • \$\begingroup\$ It looks correct to me \$\endgroup\$ – Felice Pollano Jan 14 '13 at 9:50

In your simulation you have placed the GND at one end of the AC supply. When you measure the voltage at the DC+ and the DC- points of the bridge with respect to the GND this is what you will see.

Place your GND reference at the DC- point and then you will get what you expect.

enter image description here

enter image description here

  • 3
    \$\begingroup\$ ... and precisely for the reason that there's a difference between the AC reference and the DC reference (a.k.a. GND): Never put the clip of an oscilloscope probe to the DC reference (GND) when troubleshooting mains-connected bridge rectifiers (except when you float your D.U.T. with a transformer). The clip, via the scope, is connected to the AC reference (a.k.a. PE or PEN), and things will go boom! if this detail isn't respected... \$\endgroup\$ – zebonaut Jan 14 '13 at 9:58
  • \$\begingroup\$ @micheal, which simulator have you used in your answer? \$\endgroup\$ – skyfoot Jan 14 '13 at 12:01
  • \$\begingroup\$ Looks like LT Spice \$\endgroup\$ – Martin Jan 14 '13 at 12:59
  • \$\begingroup\$ Yep, that's LTSpice - I'm sure Micheal is aware of this, but since it seems relevant, a tip for differential measurements for anyone else who is relatively new to it, is to click and hold the left mouse button on one node, drag it to the other node (the probe will should turn black) and release. You will now get a trace that is the difference between the two nodes (instead of e.g. one node and circuit ground) It will be labelled something like V(N001, N002) \$\endgroup\$ – Oli Glaser Jan 14 '13 at 15:10
  • \$\begingroup\$ @All - Oh I am fully aware of how to use the probing in LTSpice to do the differential measurements. My intention of actually moving the "GND" connection was so that I could show <b>skyfoot</b> how to correct his simulation. I have no idea if his Android simulator has the differential measurement concept implemented in it. \$\endgroup\$ – Michael Karas Jan 14 '13 at 16:01

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