Phase, Pulse and Frequency

Phase

number of wave cycles in a circuit

Most basic alternating current

single phase

Single phase

1 distinct waveform

Voltage drops from maximum to 0 in between pulses in

single phase

Single phase half wave rectified

1 distinct waveform, half rectified, 100% voltage ripple

Original x-ray tubes were

single phase half wave rectified

Gaps in x-ray production in

single phase half wave rectified

Single phase full wave rectified

reversing electrons are not blocked but converted to same direction, voltage drops to 0 still but with no gaps

Main disadvantage of single phase

voltage ripple

Voltage ripple

change in voltage with each pulse

100% voltage ripple means

voltage fluctuates from the maximum all the way to the minimum (0!!!!)

100% voltage ripple is bad because

the beam has less energy, less intensity, less energy, there's fewer photons and less penetration -> not as many photons making it to the patient

3 phase alternating current

3 different waveforms creating the current through the circuit

Three-phase alternating current still has to be

rectified for the x-ray circuit

3 phase 6 pulse

6 pulses per wave cycle

3 phase 6 pulse has a voltage ripple % of

14

3 phase 12 pulse voltage ripple %

4

Most modern x-ray machines powered by

high frequency generators

High frequency generators

thousands of pulses per cycle and basically 0 loss in voltage

High frequency voltage ripple %

1