# Why we need resistors

1. Jun 26, 2008

### Jin S Zhang

Why do we need resistors in every electronic circuit?

2. Jun 26, 2008

### mgb_phys

You don't need them in EVERY electrical circuit, but since they change the voltage/current and electrical circuits are all about voltage and current they do tend to come in handy!

3. Jun 26, 2008

### Jin S Zhang

Why we don't need them in every circuit? How are they handy? What would happen if there was no resistors in some circuit?

Please explain me coz I know nothing about electricity and just started learning.

4. Jun 26, 2008

### Staff: Mentor

Resistors are used for many things, often for controlling impedances and dividing down voltages. It would be best if you read some about resistors, and came back with specific questions if you still have them. Here's a starting point:

http://en.wikipedia.org/wiki/Resistor

Also, if you can find or buy a copy of The Art of Electronics by Horowitz and Hill, that book will take you from the very basics of resistors all the way through an introduction to basic electronic circuits.

5. Jun 26, 2008

### waht

If you connect an LED diode to 12 V it will burn out quickly. But if you connect a proper resistor to the LED, then it will limit the current to the diode and it will not burn out.

6. Jun 27, 2008

### envytea

JSZ,
Please check out an article (WikiPedia) on Ohm's Law. This is probably the very best place to start learning about electronic circuits. There is a well-defined relation between a circuit's voltage, current and resistance. All of these terms have their own definitions that will make sense in time, but check out Ohm's Law first.

Resistance is a property of 'work' having been done in a circuit. Not only do resistors make resistance, but motors, lights, induction coils, diodes, wires themselves, and many others create resistance too.

I am glad that you are asking this question. I assure you that you will soon discover some really amazing things about our world. Good luck. Let me know if you have any more questions.

7. Jun 27, 2008

### Redbelly98

Staff Emeritus
The very first thing to learn is what voltage and current are. If you don't know that, nothing else will make any sense.

After that, resistance is the next basic concept usually taught in electronics.