Quote:
Originally Posted by AdrianF
I placed an order for the PTN78000W from Texas Instruments as a free sample on the 19th Dec had notification they posted it on 20th Dec and it arrived by FedEx on the 23rd Dec free of charge. I will now spend some time building the rest of the circuit after xmas, I may just use a zener on the output so that if it goes over voltage my camera has some protection. All I have to do now is decide which battery I am going to sacrifice.
Adrian
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Hi Adrian.
Funny timing of your post. I just picked up an adjustable voltage regulator from Jaycar & a few bibs n' Bobs to make the linear regulator. I'll be adding an overvoltage SCR crowbar..a bit crude but a last resort fail safe.
This is probably not needed as the regulators are pretty much self regulating & have over-current/temperature shut-downs in any case.
But..piece of mind.
I'll be running it from a 12V source and using
this canon battery adaptor...when I order it...for a 450D. Its a bit expensive ...I don't have a cheaper option of an old battery to pull apart.
I noticed my camera has a rubber grommet cut-out for power leads to feed into the battery compartment, so you can close the battery cover with the leads connected.....so it's designed for a remote supply...neat!
If you are using some zeners as last resort limit on the output...just put in a resistor in series with them to limit the current thru the zeners (to slightly below the zeners power rating).
If you want lets say 8.6 Volts as an overvoltage limit...you can put 2 zeners in series. I am doing exactly this...a 3.9V & 4.7V zener to give a total of 8.6 Volts...my max overvoltage limit.
Anyway it's interesting to so other heading up the same path!
Merry Xmas!