more help on h-bridge

[shri_sam]

how does this H-bridege works

and the poroblem that i am facing right now is that, i couldnt find the transistor NTE262 and TIP110, are there any other transistor that i can use.

what i have to do is that i have to take a voice signal which is processed using the voice recognition tools and if the right voice is there, then to run the motor to open the door or close.

so r there any other transistor that can help me.

thanks for any reply

[Guest SM2GXN]

Hi shri_sam!

As I see it, one side of the motor has to be connected between emitters of Q3 & Q4 and the other side between emitters of Q5 & Q6.
When point A  ( B low ) is high current is flowing through in turn: Q5-motor-Q4 to ground.
If B high ( A low ) the motor will change direction, current will then flow trough in turn: Q3-motor-Q6 to ground.
Replacement for TIP110 : BD715, BDW23A, BDW53A, BDW63A
and for the NTE262 = TIP115 which should be the complementary for TIP110.
Replacement for TIP115: BD716, BDW24A, BDW54A, BDW64A.
There is probably people here on this forum having better knowledge in H-bridges, let us here what they say :)

Bjorn

[shri_sam]

thanks for the reply

additionally my mentor told me to use 2 555 timer at the output of the h-bridge and then to connect to the motor.

since i dont see any logic behind using the 555 timer at the output.

so is it good to use the 555 timer at the output of the h bridge to control the movement of the motor. if it can be use they can any one tell me about the why and how can they be used
in the h-bridge.

thanks for any reply

[Guest SM2GXN]

Hi shri_sam!

Your mentor probably mean that the two 555 are pulse drivers for the inputs at the H-bridge.
With the help of the 555:s you can PWM the motor and thus regulate the speed of the motor.
For further improvement of my statement and description of any PWM circuit with a 555 and H-bridge someone with better knowledge got to step right in  ;D

Bjorn

[shri_sam]

Well yes

That was what exactly my mentor had told me to do, so when u guys told that adding the 555 at the output was the wrong idea then he told me that he wanted it to be added at the input to enhance the performance of the h-bridge.

So what u guys think about it?

Here is how my mentor wants to add the 555 timer

thanks for any reply

[Guest SM2GXN]

Hi shri_sam!

The two 555,s will do no good if they are placed at the output of the H-Bridge.
They will enhance the performance in one way ore another  ;D speed of the motor can be regulated and the transistors will dissipate less heat.

Bjorn

[shri_sam]

hi all

I came up with this idea to use to XOR gate and feed the output of the XOR gate to the input of the 555 timer so that the two timer acts in the reversible fashion meaning when one is on next one is off and vice versa.

So, i think that this idea might work but m still little suspecious about this idea, any help on this matter is helpful

thanks for any reply

[ante]

Hi shri sam,

It’s a bit dangerous to use the 555s as drawn in the schematics, try to use only one. If they switch on at the same time you will destroy parts of the circuit! :o

[Guest SM2GXN]

You are so right Ante, needless to use two 555 am I on right track if I say that the only thing you have to do is to alter the output from the 555 to input A & B?

Bjorn

[ante]

That would be much safer and I recommend a pull down resistor for each base too (Q1 & Q2) when not connected to the pulse (555). ;D

[ante]

I found another simple H-bridge at :
It’s looking good, doesn’t it?

[Ldanielrosa]

Am I the only one who disagrees with the layout of this H-bridge?

[Kevin Weddle]

One thing about the 555. This is a very simple circuit that does strange things. It is best, if you are going to use one, to figure out what the circuit will do if you are able. I have spent hours upon hours with even the simplest of circuits to figure out how they work. So be wary, you may find that that the 555 is not the best circuit for your application.

[shri_sam]

Well now I have thought about using one 555 timer, whose one

[shri_sam]

Depends on the propagation delay of the switch where both sides are on at the same timefor a brief instant
of 20 - 60 ns will cause you problems? ???

i think that the 20-60 ns will not coz that much problem.

but if it does then how can i overcome it


thanks for any reply