a) If the firing angle is set for alpha=(pi/3) estimate the power dissipated in the bulb if it is rated at 100 W and the voltage source is 230 V @ 50 Hz.
b) An anomaly that can occur in controlled rectification is drift of the firing
angle on one half cycle, so causing an asymmetrical waveform, as illustrated opposite. State the effect, if any, this would have on the harmonic content of the waveform.
The Attempt at a Solution
1a) So first of all i found the Vpeak of a normal sine wave in this case 230/0.7071 = 325V and found R=230^2/100=529ohms. I then found the Vrms for any waveform and set my boundaries and got 325*0.63423.
so Vrms = 206.12475V for this wave form including the firing angles (where those sections would = 0). I then used PT (or total dissipated) =Vrms2/R=(206.12475)2/529=80.31w which is my answer.
1b) I've found through my notes that if the phase angle of a harmonic changes it has no reference on determing the average power so that would be the same. However it would change the instantaneous power as it'd would be delayed by whatever the shift is. Is the correct or do i need to show more?