# 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 1 of 3.

Hari said:   2 years ago
Half wave
Vavg=vm/π
Vm=vavg*π
Vm=12*π
= 37.69.

Vrm=vm/2.
= 37.69/2,
=> 18.84.
(2)

ABIAS UG said:   2 years ago
Vav = 0.636Vpk.
Vpk = Vav/0.636 = 12/0.636.
=.18.867925,
Vrms = Vpk/√2.
= .13.34.
(1)

RENJITH K N said:   2 years ago
Average voltage;
Vavg=Vmax/π=12v ----> 1.

We found rms voltage = Vrms=Vmax/2 ------> 2.

From equation 1 Vmax=Vavg x π
= 12 x π
= 12 x 3.14,
= 37.68.

Applying equation 2 Vrms=Vmax/2.
= 37.68/2 .
=18.84.

Ancy said:   4 years ago
Thanks @Kiran V.

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

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)

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.

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.

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.

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