resistor size to safely dissipate current

Hi, I saw an amplifier tech on Youtube show how to dissipate current from the rectifier (on a tube amplifier) to ground while he worked on a section that was close in proximity to the diode rectifier section. He called for a 40K 20 watt resistor to be used. I can't find one that big but I do have a 10K 50 watt resistor. Would that work? What thought process would you use to know how small you can go. I believe his amp had no pwr xfrmr so the voltage on the rectifier would have been 115V x 1.4 (as far as I can assume).

by murfbass
February 02, 2019

1 Answer

Answer by getwood

If you simply want to replicate his rig, two 20K 10-watt wirewounds (at under $6.00 CDN each) will work; in fact, separating them like this would have some advantages, chief amongst them better heat dissipation.

See, for example, this:

+1 vote
by getwood
February 04, 2019

Your Answer

You must log in or create an account (free!) to answer a question.

Log in Create an account

Go Ad-Free. Activate your CircuitLab membership. No more ads. Save unlimited circuits. Run unlimited simulations.

Search Questions & Answers

Ask a Question

Anyone can ask a question.

Did you already search (see above) to see if a similar question has already been answered? If you can't find the answer, you may ask a question.

About This Site

CircuitLab's Q&A site is a FREE questions and answers forum for electronics and electrical engineering students, hobbyists, and professionals.

We encourage you to use our built-in schematic & simulation software to add more detail to your questions and answers.

Acceptable Questions:

  • Concept or theory questions
  • Practical engineering questions
  • “Homework” questions
  • Software/hardware intersection
  • Best practices
  • Design choices & component selection
  • Troubleshooting

Unacceptable Questions:

  • Non-English language content
  • Non-question discussion
  • Non-electronics questions
  • Vendor-specific topics
  • Pure software questions
  • CircuitLab software support

Please respect that there are both seasoned experts and total newbies here: please be nice, be constructive, and be specific!

About CircuitLab

CircuitLab is an in-browser schematic capture and circuit simulation software tool to help you rapidly design and analyze analog and digital electronics systems.