Quote:
Originally Posted by rick-l
Radio Shack will have one of these LM317 Got to page 7 to set the output voltage. Note that on page 3 it says VI – VO Input-to-output differential voltage is a minimum of 3.
Now add up how much current will be drawn by all the devices. Multiply that number by the Highest expected input votage minus the voltage you set the regulator to. This wil give you Watts dissipated in the junction of the pass transistor. Multiply that number by 19 deg C per Watt (theta junction to ambient for TO-220) and make sure that number is less than 150 deg C.
Edit: and since you now have measured the current divide the amp-hour capacity of the battery by that number and see how long it will work. 
Edit: Edit: If you register with TI and put your buisness name along with engineer or student somewhere in the application they will send you samples of almost anything you need. |
Wow rick I didint get all that the first time through but it looks like a good explanation, I will do exactly that.
Lube: I designed, built, and will install the system myself. I just graduated as a mech eng and my company gave me the task and almost unlimited funds to make prototypes for 5 locations (pictures shows one). Each component on the board is anywhere from a few hundred dollars to over a thousand. The great news is that everything works! The SCADA program I'm using is also very cool.