Half-wave rectifier question

[J0RJO]

Hello,

i want to ask something about half-wave rectifier simulation circuit.

why Vd is 4,5V?

i think the correct answer should be:

Vr=5V Vrms=0,707*VP=3,5V

If we consider and V draw in diode...should be around 2,7V.

I would be glad if you would answer me.

Regards, Jorjo

[pfalstad]

Well, the input is 5V, and there's about a 550mV voltage drop across the diode at that current (about 7mA), so that leaves 4.45V.

Why is the rms voltage relevant here? 4.45 V is the peak voltage.

[J0RJO]

Thank you for your response.

in the attached picture, my mouse is over resistor.

i don't see the Vdc. I see only Vmax, but after diode we have Vdc, right?

(i also create that circuit in Multisim, to try help you understand what i am trying to say)

Regards

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Από: Paul Falstad notifications@github.com Στάλθηκε: Τρίτη, 1 Δεκεμβρίου 2020 12:14 πμ Προς: sharpie7/circuitjs1 circuitjs1@noreply.github.com Κοιν.: J0RJO jorjo.satiros@hotmail.com; Author author@noreply.github.com Θέμα: Re: [sharpie7/circuitjs1] Half-wave rectifier question (#525)

Well, the input is 5V, and there's about a 550mV voltage drop across the diode at that current (about 7mA), so that leaves 4.45V.

Why is the rms voltage relevant here? 4.45 V is the peak voltage.

— You are receiving this because you authored the thread. Reply to this email directly, view it on GitHubhttps://github.com/sharpie7/circuitjs1/issues/525#issuecomment-736088263, or unsubscribehttps://github.com/notifications/unsubscribe-auth/AR6LC7PNIG2673HJHCGM6STSSQKNHANCNFSM4UIFJISQ.

[pfalstad]

Your picture didn't get attached. If you want to attach a picture, you have to go to github and do it. You can't reply with an attachment in email.. The attachment will be ignored.

[J0RJO]

i upload them in ImgBB.

if this dont work, i will reply in my post in github.

https://ibb.co/gZyrRs0https://ibb.co/gZyrRs0https://ibb.co/HPfJVSb

https://ibb.co/HPfJVSbhttps://ibb.co/gZyrRs0https://ibb.co/HPfJVSb

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Από: Paul Falstad notifications@github.com Στάλθηκε: Τρίτη, 1 Δεκεμβρίου 2020 12:28 πμ Προς: sharpie7/circuitjs1 circuitjs1@noreply.github.com Κοιν.: J0RJO jorjo.satiros@hotmail.com; Author author@noreply.github.com Θέμα: Re: [sharpie7/circuitjs1] Half-wave rectifier question (#525)

Your picture didn't get attached. If you want to attach a picture, you have to go to github and do it. You can't reply with an attachment in email.. The attachment will be ignored.

— You are receiving this because you authored the thread. Reply to this email directly, view it on GitHubhttps://github.com/sharpie7/circuitjs1/issues/525#issuecomment-736094207, or unsubscribehttps://github.com/notifications/unsubscribe-auth/AR6LC7ML3LCR47WUNPQTRA3SSQMALANCNFSM4UIFJISQ.

[J0RJO]

broken link, sorry

https://ibb.co/gZyrRs0 [https://i.ibb.co/qYBDrbH/2.jpg]https://ibb.co/gZyrRs0 2https://ibb.co/gZyrRs0 Image 2 hosted in ImgBB ibb.co

https://ibb.co/HPfJVSb [https://i.ibb.co/T0xCkf7/1.png]https://ibb.co/HPfJVSb 1https://ibb.co/HPfJVSb Image 1 hosted in ImgBB ibb.co

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Από: Paul Falstad notifications@github.com Στάλθηκε: Τρίτη, 1 Δεκεμβρίου 2020 12:28 πμ Προς: sharpie7/circuitjs1 circuitjs1@noreply.github.com Κοιν.: J0RJO jorjo.satiros@hotmail.com; Author author@noreply.github.com Θέμα: Re: [sharpie7/circuitjs1] Half-wave rectifier question (#525)

Your picture didn't get attached. If you want to attach a picture, you have to go to github and do it. You can't reply with an attachment in email.. The attachment will be ignored.

— You are receiving this because you authored the thread. Reply to this email directly, view it on GitHubhttps://github.com/sharpie7/circuitjs1/issues/525#issuecomment-736094207, or unsubscribehttps://github.com/notifications/unsubscribe-auth/AR6LC7ML3LCR47WUNPQTRA3SSQMALANCNFSM4UIFJISQ.

[pfalstad]

Looks about the same.. Multisim looks like it peaks at about 4.5 V according to the scope.

I don't know why the multimeter is reading 1.3 V.. That doesn't seem to match what the scope is reading. But I don't know if that's instantaneous or an average.

[J0RJO]

Now, i understand. In resistor, you keep measure the Vpeak. No the real voltage.

Just in case, i explain myself:

We have 5Vmax (Vpeak)

After Diode we have Vdc.

1) Vdc=Vmax/3,14=5/3.14=1.59V

2) Vdc=Vrms*0.45= *3,5V0.45=1.57V

[*Vrms=Vmax0.707=3,5V]

3) Vdc=0.318*Vmax=1.59V

with these 3 formulas, we can find Vdc (the voltage we can measure with a voltometer-the real voltage).

Thank you for your reply.

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Από: Paul Falstad notifications@github.com Στάλθηκε: Τρίτη, 1 Δεκεμβρίου 2020 12:37 πμ Προς: sharpie7/circuitjs1 circuitjs1@noreply.github.com Κοιν.: J0RJO jorjo.satiros@hotmail.com; Author author@noreply.github.com Θέμα: Re: [sharpie7/circuitjs1] Half-wave rectifier question (#525)

Looks about the same.. Multisim looks like it peaks at about 4.5 V according to the scope.

I don't know why the multimeter is reading 1.3 V.. That doesn't seem to match what the scope is reading. But I don't know if that's instantaneous or an average.

— You are receiving this because you authored the thread. Reply to this email directly, view it on GitHubhttps://github.com/sharpie7/circuitjs1/issues/525#issuecomment-736097847, or unsubscribehttps://github.com/notifications/unsubscribe-auth/AR6LC7L3IEC4AHTM3MCXNT3SSQNCJANCNFSM4UIFJISQ.

[pfalstad]

The Vd is actually the instantaneous voltage across the diode at that moment, not Vpeak. For Vpeak you need to look at the scope view.

[J0RJO]

Yeah, you just want to show the 0,7v drop in diode.

i was caring about Vdc (the real voltage which we will take parallel of the resistor)

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Από: Paul Falstad notifications@github.com Στάλθηκε: Τρίτη, 1 Δεκεμβρίου 2020 12:50 πμ Προς: sharpie7/circuitjs1 circuitjs1@noreply.github.com Κοιν.: J0RJO jorjo.satiros@hotmail.com; Author author@noreply.github.com Θέμα: Re: [sharpie7/circuitjs1] Half-wave rectifier question (#525)

The Vd is actually the instantaneous voltage across the diode at that moment, not Vpeak. For Vpeak you need to look at the scope view.

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