This is a very simple article, just trying to help ….
What is the most vital piece we always need in electronics? The answer is …. a good power supply, right? 
.
The best regulators for using in electronic projects are the 78LXX (78L05, 78L09, 78L12, 78L15 … ). I searched google for the application notes and I found them easily (look in the bottom part of the page for the download link).
Their typical application was the IC + 2 small condensers (the input is at 0.33uF and the output is at 0.01uF), but after some tryouts and more googling I found this page which, too be honest with you, I consider it to be the best circuit over the web.
I tested the circuit and it worked like charmed.
Reading the application note we see that the input voltage must be between 7V and 20V and the output voltage is between 4.75V – 5.25V .
Components:
- IC1 = 78L05 / 7805
- D1 = 1N4007
- C1 = 100uF
- C2 = 10uF
Bibliography :
- http://www.pmb.co.nz/psu_general_1.htm – the article I wrote about above
- http://www.national.com – The official manufacturer page
The 78L05 Datasheet : http://www.national.com/ds/LM/LM78L05.pdf
Hi,
To what pin of the computer(i.e in the DB25 connector) do we need to connect the input of this voltage connector ?
I suggest you not to take power from any computer port. Anyway, the voltage from a computer port is already regulated.
Regards
Sorin
can i implement this +5V regulator on a breadboard?
hey sorin,
i need a similar circuit for my project but i want the input voltage to be max 6 volts coz my device will have to run on a battery.
plz reply as fast as possible
regards
pramuk
rethabile .. yes you can
pramuk .. you can use LM317 to build such a regulator
Regards
Sorin
this reguletor data sheet was not be downloaded
by the server plese uload new data sheet
Hi Wala,
Thank you for letting me know of this, I’ll upload it again in few seconds.
Best regards
Sorin
Hey Sorin,
Your power supply circuit works perfectly.Thanks a lot! I’m not a professional…so please dont mind if my questions sound a bit silly. Can you explain what exactly are the functions of the two capacitors connected at the input and output? If we dont use the caps, there seems to be drop in source voltage. Why is that?
Regards,
Ron.
Hi Ron,
The C1 and C2 are pretty important as they keep the 78L05 stable ( they have a tendency to oscillate in certain conditions ).
Hope this helps
Sorin
Is it possible to use a LM7805CT to drive it? and what capacitance should i use for C1 and C2 if LM7805CT can be used?
WaiC .. you can use it exactly as 78L05 without any issues.
Regards
Sorin
Hey,
I’ll start by saying I’m new to this.
I was trying to build my first power regulator circuit, followed a diagram and all seemed fine.
When testing, connected to a 9v battery (9,5v brand new) the circuit output was 8,9v representing a 0,6 v diference.
I checked all the circuit, replaced capacitors and the 78L05 as well just to be sure. Got the same result.
Lowering the input to 7,5v the power output had 6,9 wich represents the same 0,6v in diference.
After this I even tested it alone with no capacitors and got the same result.
What is happening here? Am I so unlucky I got two malfuncioning power regulators?
Is there any other possible explanation?
Thanks for any help.
Hi Paulor,
Are you sure you are connecting the 78L05 ok? Please take a look at http://www.national.com/ds/LM/LM78L05.pdf for pinouts.
Regards
Sorin
Thanks Sorin,
That was it. Incredibly I did download a similar document and had a very good look at it until I was sure to be getting it right. It’s obvious I didn’t. So many trys and never swiched it because I was so sure to be doing it right. No heat for me meant everything fine. Only now I understand that it heats when you invert its polarity that is completely diferent. Thank you very much for even replying to a dum question like this but it really helped.
Best regards,
Paulor
No problem Paulor, glad I could help
hey i want construct +/-5 volt supply please help me
Thank you for the article and schematic .. work perfect for me!
Easy and effective; thanks for the tip.
Hey is there any way to calculate +5V regulator using 78L05 / 7805 circuit (the above circuit) please?
thanks for the circuit and what is the purpose of diode in it?
The diode is there as a protection for misplacing + with – (reverse the INPUT powering wires)
HTH
Sorin
Hi,
what’s the difference between the 7805 and the 78L05?
what values of C1 and C2 if LM7805 will be used?
do we need filter before it pass by C1?
sir i want to make a regulated powersupply using 5regulator e.g 7805 ,7809,7812,and also 2regulator which give me -ve supply . please help me out.
Just built it for a project – worked great! I used a 1N4004 instead of a 4007 though. Thanks!
Hi, this is my 1st post here. An interesting alternative to this classic IC is the MC34063
switching IC which is commonly used in cellphone car chargers. It is pretty effecient and simple to use, and you can usually use the PCB as is. It is also voltage adjustable and there is a very handy design tool available at http://www.nomad.ee/micros/mc34063a/index.shtml. The IC is dicontinued from major suppliers, but easy to find at thrift stores. Usually, as supplied in chargers, it’s good for about half an amp, but can supply much more with a power transistor and a 5 to 25 uH choke. Datasheets are on the web. Oh, use a switching frequency between 30kHz & 180kHz – higher is better.
Please give the voltage for C1 and C2.
how about amp that this VR can produce?
WHY WE USE 7805 FOR 5 V CAN WE USE 7824 FOR 5 V?
Hello I’m new in the circuits field and I’m building a room temperature regulating system…. Is it are there non multi-pin And and Not gates????
hello sir please give me the complete circuit design of full wave centre tapped rectifier which ll give output as 5v dc please reply soon sir i need it urgently
Stefan,
The 78L05 is rated to output up to 100 mA. The 7805 is rated 1 Ampere. By the way, the power which the regulator must dissipate as heat is equal to (input voltage-5)*current.
If you put 9 volts in, and pull 1 ampere, this means 4 Watts are produced as heat! You may need to use a heat sink, depending upon your application. Check to see if the regulator gets hot.