using the NPN PN2222A transistor

hi very simple question. I read the datasheet for the transistor but i am having a hard time understand how to use the transistor on arduino. I have collector-base-emitter on the transistor and Which one gets the +5V, Ground and the output or input from arduino respectively??? Thats what i cant figure it out. Sorry guys that it is my first project. Thank you.

What are you DOING with this transistor?

trying to control the PowerSwitch Tail. I just can not figure out the combination of the wires. The project is due this morning I am half way through but can not figure out how to use the transistor and connect it to the Tail and Arduino.

Well a pitcher is worth a thousand words ( http://www.arduino.cc/playground/uploads/Learning/solenoid_driver.pdf )

This shows how a NPN transistor is commonly used to allow an Arduino output to switch devices on and off that require higher voltage and/or current then can be supplied directly by an output pin. This example shows operating a solenoid, but it could be any 12v device, motor, lamp, buzzer, etc. What first has to be known is the voltage and current requirements of the device that you want to operate. Only then can you pick the specific npn transistor so that it can handle that current and voltage ratings. These applications are pretty simple for a transistor in that the device will be always on or always off. Using transistors in linear applications, like audio amplifiers, etc are more complex.

Lefty

so here is what i understand from this picture. Please correct me if I am wrong For The Transistor! 1) Collector gets connected to the PowerSwitch Tail '+' and no connection to the Arduino from the Collector. 2) Base gets Arduino_Digital_output wire and nothing else. 3) Emitter gets wire from Arduino_ground & ?PowerSwitch Tail '-' ?

and that's it??? i plug my tail in to the outlet and the red light on the tail should lit up?

thakns for your patience.

1) Collector gets connected to the PowerSwitch Tail '+' and no connection to the Arduino from the Collector.

I'm sorry I have no knowlege of PowerSwitch Tail.It's not in my drawing. ;)

2) Base gets Arduino_Digital_output wire and nothing else.

Funny, I see a resistor in that drawing between the base and output pin.

3) Emitter gets wire from Arduino_ground & ?PowerSwitch Tail '-' ?

Again I know nothing of powerswitch tail and also don't know what external power source you will be using. Note that in the drawing the external voltage source negitive must wire to the Arduino ground.

canavars:

You are trying to grasp and use the material from Electronics101, without having taken Electricity101. Don't let me discourage you, I admire your courage.

A link to the PowerSwitchTail would help those trying to help you. It's nothing more than a relay in a box so lefty's diagram applies almost perfectly. You don't need the 1N4004 diode, its equivalent is already in the PowerSwitchTail.

Your (1), (2), and (3) are all incorrect. Try again with this new information.

Don

You are trying to grasp and use the material from Electronics101, without having taken Electricity101

But he said:-

The project is due this morning I am half way through

So it looks like he has not being paying attention in class.

Congratulations Arduino forum members, another life has been saved from future adverse poverty, and just in the nick of time. ;D

Lefty