Im trying to make a mini RC car using an Attiny85, im going to be using an hbridge for the motor control. The problem that i have is that i only have 3 available pins to use for the motor control since 2 of the available 5 pins are being used by a bluetooth module. My question is if there is anyway to control an hbridge to go backward, forward, left and right, but do using only three input pins. Thank you in advance.
on the diagram u show in the beginning what is the name layout for pins on the transistors nd do u have all the same or u have npn type as well ass pnp type?
Thank you so much bro I have been doing so much research on making this h-brige circuit and I had the parts the who'll time. Lol. Man that's funny also great job your circuit is big but obviously we are both still learning and it's not size of a circuit we need to worie about right now it's learning how they function.
npn is slightly more efficient than pnp in purely switching applications. I think that's the only reason this setup exists. PNP has it's place, but adding a digital interface to an analogue motor probably isn't the best place for them.
hey bro this circuit helped me a lot. but got another problem. i connect 5v, 6v and even 9v with the collector but in all the cases my bjt emitter shows only 4.5 v. i need minimum 6v :( do you have any solution to this problem?
It looks like he's using 4 npn transistors with a simple resistor protecting the gate of each. The dead give away is the manner in which the gates are coordinated. since the cross the h-bridge diagonally, you're actively turning both gates on, rather than turning one gate on and one gate off (which would be 2 npn and 2 pnp transistors). As a matter of efficiency, PNP transistors are not used alone for an H bridge. They heat up much more quickly relative to NPN transistors, and designing to only use npn or npn-pnp is much easier.
can anyone explain to me, in this circuit what is the function of each transistor? I've been reading a lot of stuff but can't seem to grasp what exactly they are doing. I would guess that Q1 and Q4 are amplifying the current which will make the motor spin faster? but what about the bottom ones, Q2 and Q3? please if anyone can explain I'd appreciate it
Certainly. They are allowing digital control of an analogue device. In this setup, only two transistors are on at a time, and that forces the current to follow a certain path. In this setup, that path is across the motor in different directions. This ability to flip current is needed to control motors and to ensure a frequency is maintained in certain applications (take inverters for instance). The Transistors are not actually adding gain. They are either switched on or off. Gain would actually be bad, because that would allow resistance to the current through one or more transistor. The point of the circuit is to channel that power through an inductor (motors and transformers are inductors), and resistance in a transistor is lost as heat. For more info check out Afrotechmods channel here on youtube. he does one specific for a H bridge, and it's setup is slightly different so you can tell the difference.
no microcontroller? what are the transistors for? i thought transistors where to supply energy from another source, but you only have one source. electronics noob here
i think hes trying to protect the battery. when the motor stops it generates a voltage backwards up the bum of the circuit. gotta stop that yuckyness from damaging ya battery or arduino
hey bro this circuit helped me a lot. but got another problem. i connect 5v, 6v and even 9v with the collector but in all the cases my bjt emitter shows only 4.5 v. i need minimum 6v :( do you have any solution to this problem?
Thank You, I've been trying to figure out a reversing switch all day.
GREAT CIRCUIT (four like transistors)! You do need to add diode protection for the transistors though.
thank you are alot, so simle yet I could not figurate it out , thank you :D
Hey man,
Thanks heaps, exactly what I needed to control my wheels on my Arduino Obstacle Car!
:)
Glad i could help. I had to do this project for school so i thought i would upload it as i couldn't find much free information on the net about it.
Nice! I'm going to use this with 4v and leds but I'll just vary the resistors.
What?
Im trying to make a mini RC car using an Attiny85, im going to be using an hbridge for the motor control. The problem that i have is that i only have 3 available pins to use for the motor control since 2 of the available 5 pins are being used by a bluetooth module. My question is if there is anyway to control an hbridge to go backward, forward, left and right, but do using only three input pins. Thank you in advance.
What happens when you press both switches at the same time? how can I guard against that? Please advise.
Hi, can I get a proper report on this?
Circuit Diagram, Working Principle, etc?
on the diagram u show in the beginning what is the name layout for pins on the transistors nd do u have all the same or u have npn type as well ass pnp type?
good work man. gonna see now if i can get an arduino to power this bad boy.
Thank you so much bro I have been doing so much research on making this h-brige circuit and I had the parts the who'll time. Lol. Man that's funny also great job your circuit is big but obviously we are both still learning and it's not size of a circuit we need to worie about right now it's learning how they function.
Back EMF might destroy your Transistors.protection Diodes?
thanks.. it really helped
better question is why dint you use the pnp type ? the p channel
npn is slightly more efficient than pnp in purely switching applications. I think that's the only reason this setup exists.
PNP has it's place, but adding a digital interface to an analogue motor probably isn't the best place for them.
thanks! so simple..
That transistors are required for a motor 6v 200mA
What size resistors are used at the base?
hey bro this circuit helped me a lot. but got another problem. i connect 5v, 6v and even 9v with the collector but in all the cases my bjt emitter shows only 4.5 v. i need minimum 6v :( do you have any solution to this problem?
Use lower value resistors.
you are yousing npn or pnp transistor
It looks like he's using 4 npn transistors with a simple resistor protecting the gate of each. The dead give away is the manner in which the gates are coordinated. since the cross the h-bridge diagonally, you're actively turning both gates on, rather than turning one gate on and one gate off (which would be 2 npn and 2 pnp transistors).
As a matter of efficiency, PNP transistors are not used alone for an H bridge. They heat up much more quickly relative to NPN transistors, and designing to only use npn or npn-pnp is much easier.
can anyone explain to me, in this circuit what is the function of each transistor? I've been reading a lot of stuff but can't seem to grasp what exactly they are doing. I would guess that Q1 and Q4 are amplifying the current which will make the motor spin faster? but what about the bottom ones, Q2 and Q3? please if anyone can explain I'd appreciate it
Certainly.
They are allowing digital control of an analogue device.
In this setup, only two transistors are on at a time, and that forces the current to follow a certain path. In this setup, that path is across the motor in different directions.
This ability to flip current is needed to control motors and to ensure a frequency is maintained in certain applications (take inverters for instance).
The Transistors are not actually adding gain. They are either switched on or off. Gain would actually be bad, because that would allow resistance to the current through one or more transistor. The point of the circuit is to channel that power through an inductor (motors and transformers are inductors), and resistance in a transistor is lost as heat.
For more info check out Afrotechmods channel here on youtube. he does one specific for a H bridge, and it's setup is slightly different so you can tell the difference.
thanks so much for this Walter, appreciate it.
no microcontroller? what are the transistors for? i thought transistors where to supply energy from another source, but you only have one source.
electronics noob here
i think hes trying to protect the battery. when the motor stops it generates a voltage backwards up the bum of the circuit. gotta stop that yuckyness from damaging ya battery or arduino
yeah but i also thought that where the diodes for, for the backlash. and there isnt any diode there...
Thanks for idea :)
Thanks
why change direction using spit rings ....
thanks very much
What's the point? No one needs to reverse direction on a motor...
The upper transistors will be pnp type.
why
wont work as the top transistors have to be p type. wont work
why
hey bro this circuit helped me a lot. but got another problem. i connect 5v, 6v and even 9v with the collector but in all the cases my bjt emitter shows only 4.5 v. i need minimum 6v :( do you have any solution to this problem?
good :)
It can be more easy if you use MOSTFET than BJT
Lol re did
why change direction using spit rings ....