Topic: Voltage Regulator Questions for JB3

[Ian]

Hey, I've got one of them TO-220 voltage regulators for dropping a an increased voltage input to 5v. It's from Radio Shack and has three prongs, one is input, one is ground, the other is output. I have a 12v battery that I'm working with. I have the regulator inline with the + cable from the battery. So I have a + line comming from the battery to the input on the regulator, then I have the middle prong grounded to a piece of metal, then I have the + line comming out from the output prong on the regulator. Well, it's supposed to bring it down to 5v, but I have the 12v going to like 10.6v. I bought a second regulator, assuming the first was fried, and it does the exact same thing, leading me to believe I've done something wrong. Any and all help is appreciated. I can post pics if that helps to clarify things, just ask. Also, I just broke open my cell phone car charger, and have the JB3 running off remote power for going on 6 hours...and I'm only 3/4 of the way dead on my Eco-Charge. Peace, -Ian

[Ian]

Here's a pic of what I'm dealing with:



Any ideas why it only drops to 10.6V and not fully to 5V?

[leegeddy]

Here's a pic of what I'm dealing with:



Any ideas why it only drops to 10.6V and not fully to 5V?

did you draw a schematic? your imput ground should be common with the output ground.

i really can't see anything from the photo except for pin2 soldered to the aluminum plate.

marc

[Ian]

Thanks Marc for all you're help. I've finally created a proper voltage regulator, as I had originally wanted to make, and will have an extremely nice finished product to present tomorrow evening. Thanks again!  Peace, -Ian

[Busman Audio]

Can you show what you did to finish this. I am looking to make one.

[tms]

Hey, I've got one of them TO-220 voltage regulators for dropping a an increased voltage input to 5v. It's from Radio Shack and has three prongs, one is input, one is ground, the other is output. I have a 12v battery that I'm working with. I have the regulator inline with the + cable from the battery. So I have a + line comming from the battery to the input on the regulator, then I have the middle prong grounded to a piece of metal, then I have the + line comming out from the output prong on the regulator. Well, it's supposed to bring it down to 5v, but I have the 12v going to like 10.6v. I bought a second regulator, assuming the first was fried, and it does the exact same thing, leading me to believe I've done something wrong. Any and all help is appreciated. I can post pics if that helps to clarify things, just ask. Also, I just broke open my cell phone car charger, and have the JB3 running off remote power for going on 6 hours...and I'm only 3/4 of the way dead on my Eco-Charge. Peace, -Ian

I don't think you have it connected right.  + and - from the battery solder to two pins on the 7805.  The output pin on the 7805 is +5V referenced to the - terminal on the battery.  It's a common ground.  Don't solder it to the plate you're mounting the 7805 to, it's just a heat sink. 

Battery +12 ------------------------ +Vin on 7805
Battery -(Ground)----------------  - or ground on 7805
+Vout on 7805 -------------------- +5 volts, solder to connector for JB3
Battery -(Ground)------------------ Common ground, solder to connector for JB3