# h bridge

Apr 30, 2013
4
0
i try to design an h bridge to drive 24 v / 5 amps motor(for a wheelchair) and connect it to arduino , i design a circuit and attached it with this post , i use TIP41/TIP42 and 2N2222 transistors in my design and i use these data form the data sheet :
HFE for the TIP41=15
V(BE) = 2 V
and for the 2N2222
HFE = 30
V(BE)=2.6
are these data correct ???
and this is the schematic...

in addition i need to just control the direction of rotation with no speed control

with thanks

Apr 30, 2013
4
0

3. ### shortbus AAC Fanatic!

Sep 30, 2009
4,095
1,683
Most people use Mosfets for that type of motor. The can handle more power than a BJT.

4. ### kubeek AAC Fanatic!

Sep 20, 2005
4,689
806
Why are Q3 and Q4 connected like that? That makes no sense.

5. ### ScottWang Moderator

Aug 23, 2012
4,930
777
In your circuit the Q3 and Q4 will make the Motor as shorted to ground, it only has 0.7V to ground, if you adding any voltage >2.1V to Q5 and Q6 and turn them on, it could be damage the Q1 or Q2, because there is no any load in series with them, there are 24V-0.7V on the Vce, so they could be damaged, Q3 and Q4 also.

6. ### crutschow Expert

Mar 14, 2008
13,496
3,373
There are numerous bridge circuits you can find with a Google search. Why not use one of those instead?

7. ### Ramussons Active Member

May 3, 2013
562
92
In Bridge circuits, the Diagonally opposite Elements turn on appply voltages on the load.
In your case, Q1 and Q4 should turn on for feeding a current Left -> Right on the motor, and Q2 and Q3 for the opposite.
You need to re design your circuit to control Q2 and Q3.

Ramesh

Last edited: May 6, 2013