Noob question 'bout transistors...

[smoguzbenjamin]

You're gonna laugh at me for this one....  

I've been looking into schematics for 'bout a month, and decided to build some things, but I wonder "why am I buying these things and putting them in? What's the point of it?" So, I know that a cap blocks DC current and acts as a high-pass filter., and I know a transistor either amplifies or acts as a swicth. But what does a resistor do?

cheers
Ben

[petemoore]

[V] Voltage divided by [R]resistance = [C]current
 There are tutorials [ I forget where exactly] explaining OHMs law, check GEO skills you need [might be there], I'm pretty sure there's something in links explaining resistors...
 Basically if you have two of the numbers of the ohms equations you can calculate the third
 Current times resistance = voltage
 Voltage divided by resistance = current
 Voltage divided by current= resistance
 This is the first time I've actually written this, if any of it is wrong well please Excuse Me !!!
                                        V
                            ___________________
       
                            R           X          C
  I believe that's the Ohm;s law chart ... with two values known the third can be calculated using this chart.
  the line under V means divide, the X means multiply. Cover on of the three values you don't have [say C] and work the equation...
  With the C covered by your hand you see: V over R ..or Voltage multiplied by resistance.
  With the R covered it's V [value] multiplied by C value = R value
  I would wait for a few to see if someone else threads here with the tutorial's page link, or blasts a correction to my little attempt...lol just hunt around for info, you'll surely find other stuff you can use....

[Switched]

It's helpful to equate basic electrical theory with water flowing in pipes.

- Think of the actual flow of water as electrical current (I)
- With a large diameter pipe, a lot of water can flow through. Conversely, a small diameter pipe will allow less water to flow through. Resistance (R) is how much opposition there is to current flowing. So, you can use resistance to limit how much current is flowing in your circuit. It also has another use - read on.
- Think of voltage (V) as electrical pressure. You can have the biggest pipes around, but if you don't have any pressure the water just isn't going to flow. Say, you want to increase the pressure in one section of your pipe circuit. You could put in a smaller pipe (a resistor) to cause the pressure to build up - just like when you squirt your sister by putting your finger in the end of a faucet If you take your pipe and branch it in two with one large pipe and one small pipe - the water in the large pipe will have less pressure (less resistance, lower voltage) than the small pipe (more resistance, higher voltage). So resistors can act as voltage dividers - a way to change the electrical pressure (voltage) around your circuit.

Hopefully this sheds some light on the subject for you. Good luck with your projects

--Matt ;^]