# Electronics - Alternating Current and Voltage - Discussion

Discussion Forum : Alternating Current and Voltage - General Questions (Q.No. 5)
5.
A half-cycle average voltage of 12 V is equal to what rms voltage?
13.33 V
8.48 V
18.84 V
7.64 V
Explanation:
No answer description is available. Let's discuss.
Discussion:
24 comments Page 2 of 3.

KIRAN V said:   8 years ago
Given;
V avg = 12 V.
Formula taken w.r.f to Full wave rectifier.
Vavg = 2*V max / pi.
Vmax = (V avg * 3.14)/2.
Vmax = (12 * 3.14)/2.
Vmax = 18.84 V.

Vrms = V max /sq.root of (2).
Vrms = 18.84 /1.414.
Vrms = 13.323 V.

Pawan said:   7 years ago
It is, 18.84.

Rahul yadav said:   7 years ago
Yes, you are correct @Pawn.

Manish yadav said:   7 years ago
We are not use half wave formula because in electrical method also use full wave formula because in case of electrical we are use in wark 5volt minimum value and more than,
5volt <12volt. So we are useful wave formula.
Iavg.=12volt,
Im=12*3.14÷2=18.84
Irms=18.84÷1.41=13.36.

Lemjr said:   6 years ago
Here, Irms=peak value(Io)/1.41.

Half Cycle means Half cycle flow in output so it is a half wave rectifier
So avverage voltage of half wave rectifier is =Vm/π.
So Vm =3.14*12,
Vm=26.64,
So rms value of HALF wave is Vm/2,
So 26.64/2=13.33.

If we talk a Avverage voltage of a complete sine wave then it is 0
So we need to Take Avvg Voltage =0.637*Vm.
Vm = 18.84,
RMS=Vm/√2.
18.84/1.414,
=13.33.

Whis said:   5 years ago

Let me explain,
For half wave rectifier:
Vave = Vpk/π
12v = Vpk / 3.14,
12*3.14 = Vpk,
Vpk = 37.699V.

To get rms of half wave rectifer:
vrms(halfwave) = vpk/2.
Vrms(half wave) = 37.699/2.
Vrms = 18.85V.

Muhammad Nouman said:   5 years ago

Explanation:

For Half Wave Cycle Vrms = Vm/2.
and Vm = Vavg x π where π = 3.14 and Vavg = 12v,
So Vm = 12 x 3.14 = 37.68.
and
Vrms = Vm/2 = 37.68/2 = 18.84v.
Vrms = 18.84v.
(1)

KIRAN V said:   4 years ago
Vrms = Vpeak x .707.
Vrms = 1.11 x Vavg.
Vpeak = 1.414 x Vrms.
Vavg = .637 x Vpeak.