### Author Topic: 5V REGULATOR BASICS...  (Read 3637 times)

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• Jr. Member
• Posts: 10
##### 5V REGULATOR BASICS...
« on: July 24, 2007, 06:15:14 PM »
Hi again!

Questions on the 5V Regulator (from the \$50 Photovore Tutorial)..

Taking the metal plate to be the "back", is this pin reading correct:  LEFT: Unregulated Input Voltage +ve, MIDDLE: GND, RIGHT: Regulated Output Voltage +ve...?

-- IS IT THE CASE that the ONLY thing that the LEFT pin is connected to is JUST the Battery's +ve input, and that all the rest of the circuit's GND go to the regulator's GND, and all the rest of the circuit's POSITIVE (+ve) red wiring goes to the RIGHT pin - the REGULATED output voltage....Yay or Nay?

--DOES THE WIRING OF THE REST OF THE \$50 circuit NEED to go BEHIND the regulator (ie the regulator stands inbetween the 6V Battery Pack and the rest of the circuit or does it not matter as long as it is connected correctly?

--Can ANYONE pls think of a way to TEST that the regulator is working correctly (with no Multimeter) just using the battery and LED(s)...?

Thanks so much...

« Last Edit: July 24, 2007, 06:34:16 PM by iCopyright_Everything »

#### paulstreats

• Supreme Robot
• Posts: 1,381
##### Re: 5V REGULATOR BASICS...
« Reply #1 on: July 24, 2007, 07:02:05 PM »
Quote
Taking the metal plate to be the "back", is this pin reading correct:  LEFT: Unregulated Input Voltage +ve, MIDDLE: GND, RIGHT: Regulated Output Voltage +ve...?

correct (as long as the pins are pointing downwards like in the picture)

Quote
-- IS IT THE CASE that the ONLY thing that the LEFT pin is connected to is JUST the Battery's +ve input, and that all the rest of the circuit's GND go to the regulator's GND, and all the rest of the circuit's POSITIVE (+ve) red wiring goes to the RIGHT pin - the REGULATED output voltage....Yay or Nay?

the batterys +ve input should go to the left pin and the batteries -ve(ground) should go to the middle pin.

the circuits power now comes from the regulator so the right pin becomes the circuits +ve supply, and the central pin is also used for the -ve ground of the circuit

Yes, the rest of the wiring needs to go behind the regulator as in the picture apart from the Servos.

Unfortunately it wont be that easy to accurately test the regulator without a multimeter.

« Last Edit: July 24, 2007, 07:08:01 PM by paulstreats »

• Jr. Member
• Posts: 10
##### Re: 5V REGULATOR BASICS...
« Reply #2 on: July 24, 2007, 07:08:57 PM »
Awesome. THANKS Paulstreats, you've really helped me understand this better!

In that case, do you know if the capacitor (the larger 220uF) should go between either:

a) the UNREGULATED input (pin1) and the middle pin (GND) or
b) the REGULATED ouput (pin 3) and the middle pin (GND)....?

And I assume it is "behind" the regulator (just wanted to double-check). Thanks mate

#### paulstreats

• Supreme Robot
• Posts: 1,381
##### Re: 5V REGULATOR BASICS...
« Reply #3 on: July 24, 2007, 07:18:52 PM »

This picture indicates that the capacitor is connected directly to the 9v power supply (not regulated), and that it goes behing the regulator (though i dont think it matters because it would seem to do the same thing either way).

• Jr. Member
• Posts: 10
##### Re: 5V REGULATOR BASICS...
« Reply #4 on: July 25, 2007, 02:56:55 AM »
Okay that's a great help thanks!!    -- I'm using a breadboard and couldn't quite decipher the underside solder connections in the tutorial so was trying to just go by the color dot schematic.

Thanks again!!

#### Robotboy86

• Robot Overlord
• Posts: 139
##### Re: 5V REGULATOR BASICS...
« Reply #5 on: July 25, 2007, 02:58:12 PM »
Topics don't have to be in caps..

just an FYI

• Jr. Member
• Posts: 10
##### Re: 5V REGULATOR BASICS...
« Reply #6 on: July 25, 2007, 06:55:09 PM »
Please help! -- I'm trying to Complete my circuit for the 5V regulator but for some reason the circuit doesn't seem to get power (no led light-up) when the regulator is in its proper place according to the dot-color schematic...

BUT, when I connect the battery pack directly (no regulator) the Chip burns up SO FAST that it singes my finger!!

I "BELIEVE" the Chip (microcontroller) still WORKS because the LED test works whether the battery's connected to pin 7 or the other side (AVCC etc)...

Does anyone know what is going on or how to correct this?! Thanks so much....

Dan

• Jr. Member
• Posts: 10
##### Re: 5V REGULATOR BASICS...
« Reply #7 on: July 26, 2007, 08:08:15 AM »
Incase you weren't sure, I am trying to complete the \$50 Robot tutorial circuitry:

I have come to a difficult juncture - wiring it all up...

You see I'm using a Breadboard (didnt want to make permanent mistakes), SO I had to try to translate all the tutorial connections

-- Basically I gave up deciphering the soldering upside down pictures and just followed exactly the super helpful color-dot schematic invention! (http://www.societyofrobots.com/images/sbs_avr_schematic.png)

HOWEVER, the problem is this:

I've just tested the circuit with the battery and WHEN I PLUG IT STRAIGHT INTO THE MAIN CIRCUIT (anywhere) IT WORKS! (the LED lights up, --all components in place except for Servos and Programmer)

HOWEVER, when I do it as it seems im supposed to - with the 5V REGULATOR in between the Battery's +ve & GND and the rest of the circuit, NOTHING HAPPENS...The regulator ONLY gets HOTTER either way, and without the Regulator the Chip starts to BURN RED HOT. At one time, the led came on but MUCH less bright than without the regulator, and quickly died out in brightness to off. -- I believe the chip still works as the LED lights up (without the regulator in place) whether the battery's on either side of the chip.

I am totally confused, I've tried switching the regulator the other way around to the diagram (i ordered 2 to be safe) and that didnt help either.

Please advise & thanks so much in advance for taking the time to help a beginner as I.

I am certain I have followed the color dot schematic correctly I have checked and double-checked. However a couple of things are not clear:

In the schematic the resistors values are not specified (we were told to order two types) for either device (LED and Photoresistors)

I have also joined all the same color dots together with wires.

And also - For the circuit to be testable (able to plug the power in for the LED test) DO all the external components have to be in place - meaning the SERVOs, the PROGRAMMER head, and the PHOTORESISTORS....? Or do i have to unplug the wires (eg power, GND etc) that lead to those components if they are not attached to the male pins?

#### dunk

• Expert Roboticist
• Supreme Robot
• Posts: 1,086
##### Re: 5V REGULATOR BASICS...
« Reply #8 on: July 26, 2007, 11:37:38 AM »
have you programmed the robot yet?
before programming just because the LED does not light up does not mean the circuit is not working.
likewise supplying the microcontroller with too much power and seeing the LED light tells you nothing other than you are damaging your microcontroller.

the first thing you want to do is test the regulator.
do you have a multimeter?
if you do, connect the regulator to your battery and test the voltage between the output and GND pins.
you should get 5V.

if you do not own a multimeter, try connecting the LED with resistor between the output and GND pins.
LEDs only work in one direction so try it both ways.

if your regulator is supplying 5V, next you want to connect it to the rest of your circuit.
i don't think there is much hope of your microcontroller working after it has heated up that much.
you will probably need to buy a new one but it's still worth trying the old one...

once you have powered the circuit properly, you have to program the microcontroller before you can judge whether things are working correctly.

i have not looked at the code but i believe the LED should light once the microcontroller is programmed.

dunk.

• Supreme Robot
• Posts: 11,680
##### Re: 5V REGULATOR BASICS...
« Reply #9 on: August 11, 2007, 10:16:24 AM »
Got it fixed yet?

Sounds like your wiring is somehow shorting power and ground. Perhaps bad soldering. Id check wiring, and get out a multimeter with the ohm function to check to see if wires are connected when they shouldn't be.

It also sounds like your LED fried.

Quote
For the circuit to be testable (able to plug the power in for the LED test) DO all the external components have to be in place
Nope, you dont need anything else plugged in.