Bridge Rectifier
Bridge Rectifier
- Four diodes make two possible paths. Whichever input terminal is positive, load current keeps the same direction.
Trace one conducting pair at a time
Swipe left or right to see the whole diagram →
- Mark the positive input terminal for this half-cycle.
- Follow a forward-biased diode to the top of the load.
- Follow current through the load and through the opposite diode to the negative input terminal.
- Reverse the input. The other opposite pair conducts, but load current still has the same direction.
Common mistake
Do not memorise four isolated symbols. Check that each half-cycle has one complete path and that both paths cross the load in the same direction.
Every half-cycle transfers power to the load
- The output contains one positive hump every half-cycle.
- Ideal full-wave rectification does not change the r.m.s. voltage. Reversing a sign does not change a squared value (9702/42/M/J/23 Q7(b)(iii)).
- Recent marking awarded separate marks for diode orientations and the load-current arrow (9702/42/M/J/23 Q7(a)).
Your turnbridge check
A 60 Hz sinusoidal input is connected to an ideal bridge rectifier. State the output-hump frequency and explain why load current does not reverse.
Show worked answer
The hump frequency is 120 Hz. A different opposite pair of diodes conducts in each half-cycle, but both pairs send current through the load in the same direction.