Free microcontroller projects with source code & Circuit

Your power supply page needs some clarification, you indicate the use of a 12VAC 500ma transformer which is in turn full wave rectified...

So it would be 16.9 volts not 12V as you indicate in the schematic. You'll also need a heatsink on the regulator as it's going to get very hot.

I suggest you use a 6.3VAC 500ma transformer (9V) as the circuit will run much cooler.
 
Unregulated or not it's much more than 12V. The 7805 will get very hot at even light loads like 100ma would be 1.2W where as a cheaper 6.3VAC transformer would only make the 7805 dissipate 0.4W.
Add to that a typical 12VAC secondary is usually 12.6VAC and after full wave rectifying would be 17.8VDC minus 1.4V for the diodes so 16.4VDC
Here's an article on power supplies.
http://www.angelfire.com/electronic/funwithtubes/Amp-Power_Supply-More_Info.html
 

bloguetronica

Joined Apr 27, 2007
1,359
Your power supply page needs some clarification, you indicate the use of a 12VAC 500ma transformer which is in turn full wave rectified...

So it would be 16.9 volts not 12V as you indicate in the schematic. You'll also need a heatsink on the regulator as it's going to get very hot.

I suggest you use a 6.3VAC 500ma transformer (9V) as the circuit will run much cooler.
I don't think that a 6.3VAC transformer would give enough voltage headroom. You must take the ripple into account. I would advice a 9VAC transformer, that would give 12.72V. Take at least 1.2V because of the rectifier bridge (I would expect about 1.6V to 2.0V), and take the ripple voltage. You will need to supply an input voltage of at least 8V at the regulator's input to get the voltage regulated. And that is the absolute minimum.
 
Here's a simpler powersupply using a 12.6VAC center tapped transformer, since it's only 1 diode drop the VDC out is 8.2V.
Less parts, less heat, same transformer.
 
Thnx to BLUEROOMELECTRONICS for giving the link,

http://www.angelfire.com/electronic/funwithtubes/Amp-Power_Supply-More_Info.html


This link has helped me, for designing a power supply circuit for my microcontroller....

I into Hardware designing. I am an fresher with very less knowledge on Electronics. So, if anyone has useful links like this, which will help me to design the circuits , calculate the values & choose components for some very basics projects, right from scratch... It ll help me a lot for my future....

So post me links if u have any.....


Thanks in Advance...... :)
 

Toughtool

Joined Aug 11, 2008
15
If you look at the very top of the page, there is a row of blue buttons with extensive and well written tutorial material, including worksheets and experiments. For those who know nothing about electronics, start with "Vol 1-DC". Joe
 

maxpower097

Joined Feb 20, 2009
785
Looks good, but I might suggest cutting back on the Google Ads a touch or at least remove the top ones. Makes the site seem spammy at first till you dig through and find theres real content there. :)
 
Top