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I want to make a bridge rectifier that can convert 230 VRMS 50Hz AC into fully rectified DC, but I don't know what particular diode to use for my circuit.

In particular, I want to use Schottky diodes due to their increased efficiency and minimal power loss but all the diode combinations I have tried so far haven't worked.

Here is my current diagram where I use the MBR40250G Schottky Diode since it is 250V. enter image description here

update

here I have increased my capacitor value from 100u to 430u and this is my output enter image description here

  • update 2*

here i have updated the sine voltage to 100Vrms

final update enter image description here

![enter image description here

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    \$\begingroup\$ What hasn't worked? Did it blow up? Did it have no power output? Did it get up and eat your hamster? What does your circuit do that is wrong? \$\endgroup\$
    – JRE
    Dec 12, 2020 at 20:26
  • \$\begingroup\$ Ok sorry I am new at this but basically out of all the diodes I have tested on multisim none of the diodes shows a rectified DC wave on the oscilloscope. \$\endgroup\$ Dec 12, 2020 at 20:29
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    \$\begingroup\$ Well would you then show what you get and what you expect? We can't know that. Also, if the oscilloscope ground is same as your mains ground, then obviously it will bypass the diode bridge, and only D2 will work as half wave rectifier, and D1 will short out the negative half wave to ground. Also, schottky diodes are not usually used for mains rectification, as there usually is little need for schottky diodes at that point, and their fast turn off can cause more problems than the lower voltage drop would solve. \$\endgroup\$
    – Justme
    Dec 12, 2020 at 20:37
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    \$\begingroup\$ 230V is too high for a Schotky so even if your sim doesn't account for that and allows it to work, don't try it in real life. \$\endgroup\$
    – DKNguyen
    Dec 12, 2020 at 20:41
  • \$\begingroup\$ @Justme I have updated the question with my current circuit diagram. thanks for the input. \$\endgroup\$ Dec 12, 2020 at 20:45

2 Answers 2

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  1. Your Y-scale is too small. The line is off screen. It is a about 300 screen heights above your actual screen.
  2. your triggering also isn't set properly. You are set to trigger on positive zero cross...but this is DC. There is no zero cross to trigger off of. For now, set to auto. No trigger = no image updates. Remember this when using a real scope.

Note a 230Vrms sinusoid has a peak amplitude of 325V which is what the DC will be. Rate components accordingly. Your simulator may or may not take breakdown into account. Real life always will.

UPDATE: Looks like your simulator does take this into account since a 100Vrms source gives you the expected 141VDC but a 230Vrms source gives you 250VDC (the breakdown voltage of your diodes) rather than the expected 325VDC.

Also beware in real life...a real scope will share its ground (i.e. the probe ground clip) with the 230V mains and produce a short circuit bypassing your diodes and can blow up your scope unless the 230V is passed through an isolation transformer or you use differential or isolated probes. Simulated oscilloscopes don't have this issue.

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  • \$\begingroup\$ Comments are not for extended discussion; this conversation has been moved to chat. \$\endgroup\$
    – Voltage Spike
    Dec 12, 2020 at 22:24
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The Silicon Schottky Diode has less voltage drop than the normal Silicon diode so it would be more efficient . For good reliability in real life 600Volt devices would be suitable .Remember that mains is full of nasty spikes where multisim is not .Silicon Schottky Diodes are easy to buy up to 200Volt .The newer expensive Silicon Carbide Schottky Diodes are available in much higher voltages but they drop more voltage than the cheap normal silicon diodes .So with bare diodes there is no free lunch on mains.Placing 4 low RDs on 600V mosfets will reduce losses when arranged to bypass the 4 standard diodes .I have done this in the lab but the cost of the mosfets was too high for production .

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