Help! (5V psu problems)


I'm trying to make a 5V psu for programming my new (but not so shiny v_v) ATtiny2313's

I've got the circuit shown below set up, but I'm getting out around 5.6V, when the spec sheets say that I'm supposed to be getting out 5V (+/- .2V) I'm using the LM 340t5, just 'cause I don't have any other regs (except for the MC78M05CT, which is basically the same thing.

Any Ideas?!


I know what was wrong - it was my meter, it really was 5V all along ;)

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zachninme10 years ago
I told him, just use 2 AA's!, or 3! The ATiny's will be fine as long as you keep it under 5v.
T3h_Muffinator (author)  zachninme10 years ago
Guess what?! I got it to work!
What did you do differently ?
T3h_Muffinator (author)  Goodhart10 years ago
I replaced the batteries on my meter ;-)
Occam's razor LOL
I have never implemented a transformer into any circuits I have done, but to get my definition straight, is the transformer taking the 3V (from the 2AAs) and raising the voltage to ~5V? If my definition of a transformer is correct, it raises and lowers electricity. Correct me if I am wrong. I am somewhat confused.
Transformer keeps Wattage (Voltage * Current) the same (in reality, the wattage goes down a little) it just shifts voltage to current or vice-versa.

However, its only for AC ;-)
westfw10 years ago
Looks like it should work to me. Are you sure your meter is accurate? Got the right pins in the right place? Does the 78M05 behave the same?
T3h_Muffinator (author)  westfw10 years ago
It was my meter - the batteries were low and needed to be replaced.
CameronSS10 years ago
I'm not too good at reading datasheets...What is the difference between an LM317T and an LM340T? Is it just a different amperage rating, or what? Could an LM340T be used interchangeably in a circuit designed for a LM317T?
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