I need a voltage comparator CI

[moonstreat]

hello, I'm up a circuit, which is as follows:

**broken link removed**

- I have this engine running in one direction of rotation, and LED lights;

- But when I change the direction of rotation, the polarization change, and the LED no longer turns on!

I would like information about a CI that fassa comparison of + / - signs, so I can have the LED always lit ..

solution would be to use the 74LS32 (OR gate), but its supply is 5V ..

thank you for your help.

 

[Wade Hassler]

Here's one way

 

[moonstreat]

Thank you my friend!

I already test! D;

 

[moonstreat]

this circuit does not work .. because if I change the polarization of the entry .. the LED does not light! so it is lit in this way .. the reverse he is off!

 

[Gobbledok]

That way will work. The diodes are set up like a bridge rectifier so it doesn't matter which way the current is flowing, the diodes will correct it to run the LED. If the LED isn't lit then it is probably a construction fault.


Edit: What voltage is your motor? If it's really low then that will stop the LED coming on.

 

[Vizier87]

you'd save diodes if you used two LEDs with complementary polarity to the output pins, rather than using four diodes.

 

[Wade Hassler]

Here's a deluxe version
The LED now tells you that:
+12 supply is present
+5 supply present
Motor is on and drawing at least 1 amp
(adjust Rsense and R2/R3 ratio for specific current)

 

[moonstreat]

I realized these mounts!

**broken link removed**

only the first worked! in the image below, the LED is not lit! = \

 

[Vizier87]

they're the same man.

 

[moonstreat]

they're the same man.

polarizations are exchanged!

I tried .. did not work!

 

[Vizier87]

the diode network makes sure the current goes from A-K. it doesn't make sense just because you switched the polarity, since the diode network is a rectifier by configuration. must be something else which is the problem.

 

[moonstreat]

I'll try again .. then say something!

have you called this circuit pa know if it works?

 

[Roff]

I realized these mounts!

**broken link removed**

only the first worked! in the image below, the LED is not lit! = \

The two circuits are identical. One is just upside down from the other.

 

[Vizier87]

exactly. That's what I've been trying to tell.

 

[moonstreat]

Hallelujah!

staff, has already managed to connect the circuit ..

Today I called again and was working well!

I must have fooled me to some link!

Thank you for your attention and patience! = P

 

[Vizier87]

phew. ok good for you dude.