# 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?

Discussion:

24 comments Page 1 of 3.
Hari said:
3 years ago

Half wave

Vavg=vm/π

Vm=vavg*π

Vm=12*π

= 37.69.

Vrm=vm/2.

= 37.69/2,

=> 18.84.

Vavg=vm/π

Vm=vavg*π

Vm=12*π

= 37.69.

Vrm=vm/2.

= 37.69/2,

=> 18.84.

(2)

ABIAS UG said:
3 years ago

Vav = 0.636Vpk.

Vpk = Vav/0.636 = 12/0.636.

=.18.867925,

Vrms = Vpk/√2.

= .13.34.

Vpk = Vav/0.636 = 12/0.636.

=.18.867925,

Vrms = Vpk/√2.

= .13.34.

(1)

Muhammad Nouman said:
5 years ago

Answer is 18.84v.

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.

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)

Rahul yadav said:
8 years ago

Yes, you are correct @Pawn.

RENJITH K N said:
3 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.

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.

Vrms = 1.11 x Vavg.

Vpeak = 1.414 x Vrms.

Vavg = .637 x Vpeak.

Whis said:
6 years ago

The answer must be 18.85.

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.

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.

Shadan said:
7 years ago

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.

So we need to Take Avvg Voltage =0.637*Vm.

Vm = 18.84,

RMS=Vm/√2.

18.84/1.414,

=13.33.

Shadan said:
7 years ago

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.

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.

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