5L30.10 - Bridge Rectifiers

Code Number:
Demo Title:
Bridge Rectifiers
AC/DC Waveforms
Area of Study:
Electricity & Magnetism
Bridge Rectifiers and LED Bridge Rectifier.

Plug the Variac into the Variac inputs on the demo board.  Channel 1 of the oscilloscope is plugged into the reference trace sockets.  Channel 2 is plugged into the DC output sockets of the bridge rectifier.  The capacitor across these sockets is for signal smoothing.  As there is no load other than the oscilloscope across the DC output the capacitor must be discharged with the discharge button when you turn the Variac off.

The bridge rectifier built out of the LED'S is very nice for showing rectifier function.

NOTE: That the LED'S do not light complete legs but alternating pairs, ie. D1 and D4, D3 and D2.

  • Jeffrey Regester, "Operation of AC Adapters Visualized Using Light-Emitting Diodes", TPT, Vol. 54, # 1, Jan. 2016, p. 48.
  • Juan A. Pomarico, "Seeing Rectifiers at Work", TPT, Vol. 40, #2, Feb. 2002, p. 118.
  • Dan Lottis and Herbert Jaeger, "LED's in Physics Demos: A Handful of Examples", TPT, Vol. 34, #3, Mar. 1996, p. 144.
  • James Mahoney, "A Demonstration of AC Rectification", TPT, Vol. 18, #4, Apr. 1980, p. 318.
  • A. D. Bulman, "On Rectifiers", Model-Making for Physics, p. 158.
  • "Electrolytic Rectifier", The Boy Scientist, p. 79.
  • Freier and Anderson, "Eo-10," A Demonstration Handbook for Physics.

Disclaimer: These demonstrations are provided only for illustrative use by persons affiliated with The University of Iowa and only under the direction of a trained instructor or physicist.  The University of Iowa is not responsible for demonstrations performed by those using their own equipment or who choose to use this reference material for their own purpose.  The demonstrations included here are within the public domain and can be found in materials contained in libraries, bookstores, and through electronic sources.  Performing all or any portion of any of these demonstrations, with or without revisions not depicted here entails inherent risks.  These risks include, without limitation, bodily injury (and possibly death), including risks to health that may be temporary or permanent and that may exacerbate a pre-existing medical condition; and property loss or damage.  Anyone performing any part of these demonstrations, even with revisions, knowingly and voluntarily assumes all risks associated with them.