I've got a 7805CT regulator running off a 11.1V lipo (yes, I know it's a big voltage difference). The 7805 is powering a PICAXE, two Maxbotix EZ4 sonars, the logic voltage for a L293N, and it's giving high voltage to the '293s enable lines. When only the PICAXE and EZ4s are plugged in I get 3.3V. When the '293 is plugged in I get just over 2V and the EZ4 readings cut out.
This doesn't seem right. The regulator doesn't even get warm. Shouldn't I be able to squeeze around an amp out of this thing? I'm puzzled.
The suggestion to swap out the L293 got me thinking. Although the L293 is brand-new the voltage regulator was far from it. Just for kicks I grabbed another junked PCB with a 7805 on it from work today. After some “flood-and-yank,” a little cleanup, and a nice heatsink (from the junkpile too lol) I plugged it in and it works like a champ. I get 4.9V at the VLS pin on the '293 and the sonars return happy stable numbers. I guess I finally found a side effect of sourcing components from the junkpile… YMMV.
