problems with L293B

[moonstreat]

Hello I built a car and implemented the l293B to the direction of the engines.

I built a command wire, manual! the car was going well, but it was short lived, because the engines stopped walking .. and only go once in a while I do not know why! someone I can please you planned?

 

[crutschow]

Without a schematic it's impossible to know the problem from your fractured description.

 

[moonstreat]

this is my schedule:

**broken link removed**

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my motor is a 12V, 600mA

 

[audioguru]

The inhibit pin1 and pin9 are supposed to be connected to +5V but yours are floating.
With a load of 600mA each output of the L293 has a typical voltage loss of 1V. Then the motor gets only 3V because the supply voltage is too low. If your L293 has the max spec'd loss then the motor might get almost nothing.

 

[moonstreat]

is that I can not implement a transistor in this circuit? so I would not put current in the transistor, would only control the transistors? do you think?

is my circuit!!

**broken link removed**

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here in IC chips have more or less what I did in reality, that is through electrical pulses controlling the tension of my car. this picture, the motor will rotate to the right,

 

[moonstreat]

I got my project to work without the pin 1 and pin 9 connected, because I'm going to call?

 

[audioguru]

The absolute max allowed input voltage to pin2 is 7V but yours is 8.6V which will damage the IC.
When your pushbutton is open then pin2 floats instead of being low with a pull-down resistor which is needed.

Your pin1 and pin9 are still floating. They should be connected to +5V.

 

[moonstreat]

ok, I'll feed the 7V, the problem is that the integrated becomes saturated, it can handle up to 1A, if connected to 5V

I'm as connected to 7v, so it will work for a while! because the integrated must saturate because there is current.

I was working with it fine, but after a while the hot tava L293, and the car crashed, but ill say it worked, it worked for startups.

 

[moonstreat]

What can I do? use the transistor outputs of the engines?

 

[moonstreat]

my L293 seems a heater! : S

 

[Ubergeek63]

ok, I'll feed the 7V, the problem is that the integrated becomes saturated, it can handle up to 1A, if connected to 5V

I'm as connected to 7v, so it will work for a while! because the integrated must saturate because there is current.

I was working with it fine, but after a while the hot tava L293, and the car crashed, but ill say it worked, it worked for startups.

The L293 is a piece of crap that drops close to a volt per switch. That means that it dissipates 2W and at 80C/W means you will at that point be pushing the junction temperature to 2W*80C/W+30=190C on a 150C rated junction if you do not heat sink it.

your best best is to ditch it and use a FET chip like the ones Allegro sells.