Best NPN Transistor Choice for 12V H-Bridge With 5V Logic Input and Base Resistor

sir help me to build an h-bridge. i dont know wat specific npn transistor that i must use so that i can create an h-brige. my instructor told me to use a 12v+ supply and 5v+ input to the base of transistor...he also told me to use a resistor to the ground so that the transistor will not be shorted...please help me asap thankyou

Sir Rollie,

There are a number of factors to take in to account when selecting a transistor, and I myself am no expert at it. I'll help as far as I can though.

A few important questions:
1) What is the current requirement of the device being powered by the H-bridge? I assume it is some sort of a DC motor?
2) What is the current capacity of the device driving the transistor gates on the H-bridge?
3) Do you have any other components availiable to you? Diodes? MOSFETS?
4) Are there any other requirements? Board space? Power usage?

-Cody

ahm sir u r ryt. im using a dc motor from a dvd player. i think it is powered by 12v..
i use a TIP31... but it seems that the dc motor is so slow.. and it will rotate 2secs then turnoff then rotate again then turn off again and again.. and i dont use diodes. i just use 4 npn TIP31 transistor and the DC motor. my supply is come from a 1 power supply that have two output..12v and 5v for the base of transistor...

Here try this

Theres even a tutorial on the net if you do a search

"All you have to do is type the words as follows "Transistor H Bridge " into the search bar , followed by little mouse click, left hand button on the mouse , click the ok button on site or the little magnifying glass , a bit of research reading through a few pages and low and behold you could actually answer this all by yourself "

Here you are here are the links

http://library.solarbotics.net/circuits/driver_4varHbridge.html

below a lovley little tutorial for you which some poor sod actually took the time and the trouble to put a site up for you All at his cost ,His own time and even took the touble to learn how to write a simple page of html probably by hand as well, using note pad and dos ftp to upload to the site also costing this person money all foc for you !!

Whats up pal too difficult to manage

I wonder VI this is so hard for this person to do


http://www.nathandumont.com/node/249

Then if you look for "what is the working voltage of a dvd motor / cd motor using the same method as above ", you will get the following answer believe it or not ,as follows ....

The voltage of motor that run the CD/DVD is 3v/ 5V/12V. This motor usually have only 3 pin! The pin are the more larger track on the board. 1 common pin and 2 control pins.

Short of this if you actually took the time and the trouble to inspect a motor of an old dvd player nine times out of ten the voltage is clearly marked on the motor somewhere

Your instructor, we hope would have also discussed with you how an H bridge circuit works first and then asked you to build one

I doubt very much if the instructor would have asked you to biuld such a circuit without prior explanation of some type Even if he didnt its really not that difficult to find out for yourselves is it ?

Yes that easy

I have to say I agree fully with Mark's sentiments.
This chap it would appear, is undergoing some form of formal training, so it is reasonable to expect a fair level of self help.

Yep, need not say more except the ,"Student," is not showing up for lectures. Bu the advice, look up something and copy it, or adapt it. How hard is that, a proven circuit, copied, slam dunk.