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.
                
                        Ram said: 
                         
                        1 decade ago
                
                Imax=Irms/1.414
Imax=1.57*Iav
Imax=1.57*12=18.84
Irms=18.84/1.414
Irms=13.33V
                Imax=1.57*Iav
Imax=1.57*12=18.84
Irms=18.84/1.414
Irms=13.33V
                        Karuppasamy kpk said: 
                         
                        1 decade ago
                
                RMS value = V(peak value)*.707
V(average value)= Vpk*.637
Therefore, RMS valu =Vav*(.707/.637)
Vrms = 12*1.11 = 13.31= 13.33.
                V(average value)= Vpk*.637
Therefore, RMS valu =Vav*(.707/.637)
Vrms = 12*1.11 = 13.31= 13.33.
                        Vid said: 
                         
                        1 decade ago
                
                Why we are not directly taken formula for half wave rectifier.
Form factor= (rms/avg).
                Form factor= (rms/avg).
                        Abhi said: 
                         
                        1 decade ago
                
                Avg.value = 0.636*Max.value.
Max.value = 12/0.636 = 18.86.
but,
RMS value = Max.value/1.414.
RMS value = 18.86/1.414=13.34.
So, the option is [A].
                Max.value = 12/0.636 = 18.86.
but,
RMS value = Max.value/1.414.
RMS value = 18.86/1.414=13.34.
So, the option is [A].
                        Kaneez fatima said: 
                         
                        1 decade ago
                
                You all are applying formula for full cycle, but in question we asked to find rms for half cycle. If we apply formula for the half cycle answer may be wrong.
                
                        Sunday said: 
                         
                        1 decade ago
                
                Can same formula work for rms and half cycle.
                
                        Stp said: 
                         
                        1 decade ago
                
                Form factor Kf = (rms value/half cycle average value).
Kf for sine wave 1.11.
rms value = 1.11X12= 13.33.
                Kf for sine wave 1.11.
rms value = 1.11X12= 13.33.
                        Vinod semwal said: 
                         
                        1 decade ago
                
                Vpick = pai* Vavrag/2.
Vpick = 3.14*12/2.
= 18.84.
Vrms = Vpick/1.414.
= 18.84/1.414.
= 13.33 V.
                Vpick = 3.14*12/2.
= 18.84.
Vrms = Vpick/1.414.
= 18.84/1.414.
= 13.33 V.
                        Engineer Marc said: 
                         
                        1 decade ago
                
                This is wrong. If you use full wave formula:
Valve = 2Vpeak/3.1416 => 12 = 2Vpeak/3.14160 (Shift solve).
Vpeak = 18.8496 (full wave).
For full wave Vrms:
Vrms = Vpeak/sqrt 2 = 18.8496/sqrt 2 = 13.13 (Vrms for full wave).
The correct formula for half wave is:
Valve = Vpeak/3.1416 => 12 = Vpeak/3.1416 (Shift solve).
Vpeak = 37.6992.
For Vrms half wave its:
Vrms = Vpeak/2 => 37.6992/2 = 18.84.
                Valve = 2Vpeak/3.1416 => 12 = 2Vpeak/3.14160 (Shift solve).
Vpeak = 18.8496 (full wave).
For full wave Vrms:
Vrms = Vpeak/sqrt 2 = 18.8496/sqrt 2 = 13.13 (Vrms for full wave).
The correct formula for half wave is:
Valve = Vpeak/3.1416 => 12 = Vpeak/3.1416 (Shift solve).
Vpeak = 37.6992.
For Vrms half wave its:
Vrms = Vpeak/2 => 37.6992/2 = 18.84.
                        SAs said: 
                         
                        10 years ago
                
                For half cycle.
Effective voltage or RMS = 1.11*V average.
= 1.11*12 = 13.32 v.
                Effective voltage or RMS = 1.11*V average.
= 1.11*12 = 13.32 v.
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