Transistors

Hello. I have been trying to build an H-Bridge to control my motors.
I am having trouble figuring out what transistors to use and reading the datasheets for each transistor. I am using a motor powered by a 9 volt battery. I am also connecting this to the arduino to control it. I have a simple sketch that alternates between turning on pin 8 and 7. Any help towards what type of transistor I should use or how to interpret the datasheets will be well appreciated.

It very much depends on how many amps your motor needs.

You can buy at lowish cost shields which do this - why build your own?

In general logic threshold MOSFETS are very good, though you will need level translation to the high-side devices ( P-channel devices)

regards

Allan.

If you use transistors, you also need to make sure there is a short delay between turning the conducting Trs off and turning the other pair on. If your timiming is out, you will let the smoke out of the transistors. This is way a H bridge IC is usually used. It takes care of the switching.

Weedpharma

Google " shoot-through"+“H-bridge”

Take a look at how other’s do H-bridges

Look at what you know now and then go back and look at your original post. What does that tell you about your initiative (or lack thereof). (hint: try taking a moment to research your topic on Google BEFORE posting. It won’t kill you to do a Google search. Posting here because we are experts makes sense when there isn’t half a million links on Google about your topic. FYI, no one in their right mind today in 2016 would use BJTs (Google it) for an H-bridge. They would use mosfets. Secondly, as pointed out, shoot-through is a very serious concern with H-bridges and the reason dedicated IC’s are used,to relieve the processor of time consuming timing delay routines. There is something to be said for using BJTs for a very crude and simple demonstration, but once you have done that, throw the transistors in the garbage and get realistic. (unless you want to remain in the Neolithic Age)

Traditionally considered the last part of the Stone Age, the Neolithic followed the terminal Holocene Epipaleolithic period and commenced with the beginning of farming, which produced the “Neolithic Revolution”. It ended when metal tools became widespread (in the Copper Age or Bronze Age; or, in some geographical regions, in the Iron Age). The Neolithic is a progression of behavioral and cultural characteristics and changes, including the use of wild and domestic crops and of domesticated animals.[3]

Here’s where you started
basic-bridge.gif

Here’s the NEXT step from where you are currently at.

Here’s the NEXT step after that

Here’s where you should wind up

ezlikespie:
Hello. I have been trying to build an H-Bridge to control my motors.
I am having trouble figuring out what transistors to use and reading the datasheets for each transistor. I am using a motor powered by a 9 volt battery. I am also connecting this to the arduino to control it. I have a simple sketch that alternates between turning on pin 8 and 7. Any help towards what type of transistor I should use or how to interpret the datasheets will be well appreciated.

Why are you trying to design your own H-bridge before being competant with transistors?

You are trying to run before you can walk.

[ Start with one transistor in a switching configuration. ]

Also I see the phrase '9 volt battery' and 'motors' in the same posting which is worrying. The
normal sort of 9V battery is hopeless for high current loads like motors.