- Identify the Variables
- Write Down the Formula
- Substitute the Variables
- Don’t Forget Units!
Example ProblemDetermine the resistance of a lamp drawing 250 mA at 200 V.
I = 250 mA = 0.25 A V = 200 V R = ? R = V / I = 200 / 0.25 = 800 Ω
This book is freely redistributable for non-commercial use, with thanks to James M. Fiore via http://dissidents.com/books.htm.
When installing/removing computer hardware and other peripherals:
- Wear proper apparel. Avoid acrylic or wool sweaters when working with electronic parts. Do not wear loose fitting clothing, rings, bracelets etc.
- Unplug all computer equipment and peripherals before opening any covering cases.
- Keep your work area clean and well lit.
- Check for damaged parts.
- Do not force components into computer ports.
- Use an anti-static wrist strap or discharge yourself by touching a grounded metal object such as a computer casing.
- Power supplies produce several levels of voltage. Read the information on the power supply carefully and make sure that the power supply you are using is appropriate for the application.
- Replace all cases or coverings after inspections or installations.
- Check all circuits and installations with the instructor before power is applied.
- Retain all screws during disassembly in containers such as film canisters for proper reassembly.
- Electronic components should never become hot. Hot components means that there is a problem with the circuit. Disconnect any power immediately.
The most important safety rule of all: Always Be Careful! (ABC)
(from ICE4M Supplemental Profile Unit 1, Appendix 1.1.1)
(image from https://pixabay.com/p-624558/?no_redirect)
|Color||Digit value||Multiplier||Multiplied Out||Tolerance|
See also http://www.eeweb.com/toolbox/4-band-resistor-calculator for an online resistance calculator.