# Help Me.........

Discussion in 'Homework Help' started by ashalina, Feb 22, 2008.

1. ### ashalina Thread Starter New Member

Feb 22, 2008
1
0
I'm ashalina n new in this forum...
I've to submit an assignment of electronic tomorrow...im also new in electronic studies and my major is "Comuter and information systems"..
I do hope u guys will help me in my assignment...
Q1:Why we change Vp(peak voltage) to Vrms form in sloving problems rectifiers?
(like vp=vrms/0.707)
Q2:We have 12Vac across primary coil in a bridge rectifier and resistance is given 12Kohm...what will be the dc voltage and current for this circuit?

Regards............

2. ### thingmaker3 Retired Moderator

May 16, 2005
5,072
6

Use the formula for converting AC. Remember that E=I*R.

3. ### Salgat Active Member

Dec 23, 2006
215
1
RMS voltage is nothing more than the DC equivalent (in respect to power output). For example, 12VAC p-p is the equivalent of 4.24VDC in terms of power output. If you have two light bulbs, one with 12VAC p-p and the other with 4.24VDC, both will be the same brightness and have the same power output. Remember that RMS is calculated to include only peak to neutral, so you have to halve a p-p AC voltage when calculating RMS. Also, once you find the DC equivalent of the AC waveform, then you can use that DC equivalent to find the DC current for the circuit.