7805 + 9V battery = 6V?

vb_master · Post by **vb_master** » Sat Apr 01, 2006 8:29 pm

I want to set up a 7805 to output at least 5V. How much voltage would I be outputting with a 9V battery on a 7805?

usbcd36 · Post by **usbcd36** » Sat Apr 01, 2006 8:41 pm

5v. The 7805 is not adjustable; it outputs 5v if you give it a voltage between 7v and 32v. If you give it less than 7v, it outputs 0v. If you give it more than 32v (or 35v?), it will die. You would be outputting 5v if you wired it up to a 9v battery.

vb_master · Post by **vb_master** » Sat Apr 01, 2006 8:59 pm

Ok, good voltage. That's just about what I needed. It seems to get extremely hot though.

Post by **Skyone** » Sat Apr 01, 2006 10:30 pm

The can only handle 1.5A max, try a heatsink.

Post by **SpongeBuell** » Sun Apr 02, 2006 12:42 am

vb_master wrote:Ok, good voltage. That's just about what I needed. It seems to get extremely hot though.

That's completely normal. The way the voltage regulators works is they convert all extra voltage into heat, essentially (energy is not created or destroyed, so that extra energy needs to be used up somehow)

vb_master · Post by **vb_master** » Sun Apr 02, 2006 7:50 am

Hm, just tried it with my NOAC, and it doesn't work. I'll just use 4 AA's then.

teraflop122 · Post by **teraflop122** » Sun Apr 02, 2006 2:50 pm

9v batteries seem to offer extremely low amps, like 200mah or something to that effect. The NOAC prolly didn't start because it couldn't get enough power.

Post by **Skyone** » Sun Apr 02, 2006 2:54 pm

Nah, noac's use around 50mA, that's why everyone loves 'em.

demonofaj · Post by **demonofaj** » Sun Apr 02, 2006 3:02 pm

Running 4AA's through a 7805 for a NOAC isn't necessary, for that is what it uses right? Like prehacked the battery pack needs 4AA's.

vb_master · Post by **vb_master** » Sun Apr 02, 2006 4:01 pm

demonofaj wrote:Running 4AA's through a 7805 for a NOAC isn't necessary, for that is what it uses right? Like prehacked the battery pack needs 4AA's.

Yeah, I know because I need 6V.

teraflop122 · Post by **teraflop122** » Sun Apr 02, 2006 6:31 pm

Nah, noac's use around 50mA, that's why everyone loves 'em.

Oh wow, that's pretty slick!