Voltage Regulators
Vendor's Description:
Description:
5V Regulators
Being stupid I can never find out how much resistor and what do i know I would need to get my 7,2V Racing pack battery to turn in to nice 5V that my other components like much better.
Then what makes me happy is when some electronics is simple, like the 5V voltage regulator; You insert "whatever" into it, and out you get steady, steady 5V!!
Note that the large metal-plate is for cooling as it can get hot, so you can put a screw into the hole and put it onto some metal with a larger surface.. BUT! This metal must not be a part of the circuit, I tried that once, strange things happend, smoke..
Other types
Info on 3.3V regulators and suppliers can be found here.
Indeed this is one of the
Indeed this is one of the most important things in a robot!
The great thing about voltage regulators is that as long as your voltage supply is above a certain threshold (approx 6 V for the 7805 regulator described in the post) then the voltage regulator will keep a steady voltage of very close to whatever voltage it is made for (7805 is made for 5 V). That's not possible to do just by putting some resistors in series with your battery since battery voltage drops as the battery power is used up.
- Jimmy
Need 3 volt regulator can be ran of a 9 volt
Maybe you should have a look
Maybe you should have a look at the LM117 (datasheet here). It's an adjustable regulator meaning that you can get it to output whatever voltage you'd like as long as it's inside of the valid range found in the datasheet. Remember to add capacitors as seen in the datasheet to make the supply more stable (especially if motors or the likes are drawing power from the battery).
- Jimmy
Thanks Jimmy
Well I haven't tried it out
Well I haven't tried it out myself since I always use 5V regulated by an LM7805 regulator. I was just wondering: is your problem that you can't get the power stable (so maybe your microprocessor or something is resetting all the time?) or that you can't find a 3V regulator - or both?
- Jimmy
What I would like to know
What I would like to know is; Why do you need 3V?
.. And then I am thinking that possible the reason that you cannot get a stable 3V is that you should solder some of them blue things over each leg! (Good help, ha?) - I will find out what they are later, I have them laying over in my workshop.
/ Frits
Frits, I think maybe you're
Frits, I think maybe you're referring to capacitors? By adding electrolytic capacitors (values of 10uF or 100uF should do it) from the microcontroller's +V pin to its GND pin you create a "local" power supply for the microcontroller so it can run even if the battery supply drops for a (very) short period of time. In general you should do that with every chip you put in your circuit. When you put in a 7805 regulator you should also add same type of capacitors from the Vin to ground and from Vout to ground. This helps stabilise the power supply. Remember that electrolytic capacitors are polarized and must be put in the right orientation (or it can literally blow up!).
- Jimmy
My problem
Are you sure it will die on
Are you sure it will die on more power, like 5V?
/ Frits
I am not sure
Sounds reasonable, but I
Sounds reasonable, but I have no clue. However - I think this is a litle crazy setup :)
What do you mean by the 3v regulator not being "stable"?
/ Frits
I just Looked at the
I just Looked at the documentation for the chip, it says it could handle a 5 volt power source so i am going to buy that regulator and use it, hopefully it doesnt shorten the life of it.
Thanks Fritz and Jimmy
I knew it! 5V is king!/
I knew it! 5V is king!
/ Frits
Switching Regulators
I just bougt the switching regulator from Dimension Engineering and it works great!
http://www.dimensionengineering.com/DE-SW050.htm
It's more expensive than the trusty 7805 but also a lot more efficient. From what I'm told the traditional voltage regulator looses a lot of the extra power to heat, where a switching regulator does not. They also have a line of "any voltage" regulators:
http://www.dimensionengineering.com/DE-SWADJ.htm
http://www.dimensionengineering.com/AnyVoltMicro.htm
KA7805
So I just tore apart a broken CRT monitor specifically looking for a 5V power regulator, and it's there!!
and a plus, a lot of huge capacitors.
Careful...
LM2937 5V Voltage Regulator
I've got a 5V voltage regulator wired up to a 9V battery. to test, I've got an LED (& resistor) wired from the output of the regulator to ground and it lights up as expected. If I measure the voltage from Vin to ground, I get ~9.5V. If I measure from Vout to ground I get ~8.5V. I expected to get about 5V. Can someone explain what's going on here? I've never used a voltage regulator before, so I'm guessing this is a fundamental misunderstanding or error....
Thanks!
Graham
Complete circuit?
The datasheet for the LM2937 shows a typical application of the device with a 0.1 uF input capacitor (not so critical) and at least a 10 uF capcitor on the output (somewhat needed). See page 8 here :
http://cache.national.com/ds/LM/LM2937.pdf
Another note might be that the regulator also comes in a LM2937ET-8.0 version that might be mistakeningly read as a -5.0. The 8.5 volt reading sounds a little (or a lot) off in either case. Yet another possibilityis a meter with a battery about to give out, giving squirrely readings.
?
I dont really get wiring it, do you attach the black wire(ground, i think its called) to the center metal thing, and then the blue wire with black tape also to the center one? shouldn't that like short circuit?
sorry if its a dumm question, but im knew to the whole robotics
thing, and decided "little 8" would be my first progect"
"and just when you think your at the bottom of your hole, god hands you a shovel"
The ground is shared between
TY
ahh...
now i get it.
Thank you very much! :)
"and just when you think your at the bottom of your hole, god hands you a shovel"