Topics Discussed:
- What is a resistor?
- Parameters
- Resistor Color Code
- Ohms Law
- Types of Resistors
1. A resistor is an electrical component that restricts the flow on an electronic circuit. It reduces the voltage while passing from one terminal to the other terminal.
2. A resistor is defined by 3 parameters.
- Resistance in “Ohms” (Ω)
- Heat dissipation in “Watts” (W)
- Manufacturing tolerance (%)
3. Every resistor is color coded for the user to identify them apart. The resistance code is determined by the arrangement of the different colored bands painted around the resistor. The most common resistors have 4 bands. The first 2 bands are for the resistance values and 3rd band is the multiplier that determines how many zero’s are placed at the end. The 4th band, which is either gold or silver designates the manufacturing tolerance, the manufacturing tolerance is how accurate or close the resistor is to what the theoretical resistance actually should be. Atypical quality resistor will end with a gold band, but for critical devices, some people may need a resistor that ends with a brown or red band. (Beginners, stick with gold band resistors because it is much easier to read a resistor when you know which end to start reading it from. It if ends with a gold band every time you won’t have confusion reading it.) Some resistors have 3 or 5 bands, if the resistor has 5 bands it has a 3rd digit for the resistance value before the multiplier. If the resistor only has 3 bands it has a worse manufacturing tolerance of around 20%.
Here is a diagram showing the color code designations.
4. The resistance value you need is determined by “Ohms Law” which is V=IR.
Here is another good source. Ohm’s Law
5. Here is a diagram showing the different types of resistors and their symbols.
