regulators

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peterwaller
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Re: regulators

Post by peterwaller »

The main problem with the Pololu is it is only 600ma output.
I used the same fixed 1.5A regulator as I use for the 5V on all my controllers as Gary says you need to be carful with capacitors.
Below is the circuit for the two regulators on the special board in Flippant 2 the 6V is used to power the two servo's.
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earthwormjim
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Re: regulators

Post by earthwormjim »

Right,thats it. I'm going back to bed! :lol:
(Thanks Peter.I will come back and have a close look when my brain has warmed up a bit! :( )
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earthwormjim
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Re: regulators

Post by earthwormjim »

I am trying to use one of these...
http://www.sussex-model-centre.co.uk/sh ... p?id=35553
at 6v,it just rocks back and forth,stick input has a bit of effect,but not much. I am using it with a 6v regulator.
Do you think that 6v is too much for it??
Also,in hell boy,I am using the same regulator,and have not had any problems.(different servo.),but I have not used the central terminal,I have bypassed it,and am not using a cap either.
Isdthis ok? dous the middle terminal do anything,or is it just a terminal block??
Thanks. :)
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earthwormjim
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Re: regulators

Post by earthwormjim »

Just read that Peter uses 5v regs,so plugged it into the controller in Creepy crawly,and it is much better.So I have ordered a 5v regulator. :roll:
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BeligerAnt
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Re: regulators

Post by BeligerAnt »

That servo is only rated to 5V, it sounds like it has some sort of over-voltage protection at 6V.

Note that the 7805 is not a low-dropout regulator, it needs about 2V headroom on full load (1A) otherwise the 5V output will sag. The upside is it's nowhere near as fussy about capacitance as an LDO.

The 7805 will be OK on a 3S Li-po, although it may get a bit warm on 11.1V at full load. On a 2S Li-po the 5V will start to sag on full load at about 7V although the Li-po minimum voltage is 6V. If you are not trying to pull the full 1A out of the regulator the 7805 will fare a little better, the dropout voltage is related to the load current.

For a true LDO, try Googling "5V LDO" - National Semiconductor make several which are available from several sources. These will work down to about 6V input even at full load.
Gary, Team BeligerAnt
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earthwormjim
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Re: regulators

Post by earthwormjim »

Thanks Gary.
I have got an LDO 5v 800mah,and a non LDO 5v 1.5A coming.
I will have a play once they get here. :)
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peterwaller
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Re: regulators

Post by peterwaller »

Yes sorry about that the 7805 is just the only 5v regulator in my circuit board layout package.
The actual device used is LD29150C can be found at RS Components
http://uk.rs-online.com/web/p/linear-re ... 4E4F4E4526
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earthwormjim
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Re: regulators

Post by earthwormjim »

Thanks Peter.Thats just the ticket. :)
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