Picture of 5v Regulator
5v volt regulator circuit which can be made from only three components, its simple, cheap and easy way to get a current up to 1A and a voltage of more than 5v can only be regulated by this circuit, this circuit can be used as a bread board power supply
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Step 1: Components

Picture of components
1.............. L7805

heat sink ( a small aluminium plate from scrap)

1...............10uf 25v (electrolytic capacitor)

1................1uf 25v(electrolytic capacitor)

green LED (optional)

1k resistor(brown black red) (optional)

soldering iron


common circuit board

Step 2: Circuit diagram

Picture of circuit diagram
this is the circuit diagram of the regulator, i have added a green led in series with the 1k resistor to know whether the circuit is working, (the part is optional ) a voltage between 7v to 15v 1A current  can be given as the input.

Step 3: Steps

Picture of steps
assemble the transistor and the capacitors according to the circuit diagram in a common circuit board 

Step 4: Conclusion

most of the mistakes are formed due to poor soldering and the mistake in connecting diodes. always double check the capacitors are connected in forward bias since it explodes when reverse biased in case of electrolytic capacitor
hope this circuit will be used by the members, and if so i will bring more circuits 

Hi, thanks for sharing, Can I use an input of 24v and still in the output stay in 5v, if No what should I do, change the transistor or the capacitor values ?

xcien5 months ago

Hey ! to all instructablers out there

I was just wondering if it is ok to use two 70 microfarad capacitors .

Thanks, your replies are appreciated

TommyT1 xcien4 months ago

long story yes with an if...

short story no with a but!

the circuit is designed with a large and tiny capacitor. you could have a 900 microfarad capacitor before but you must have a less then 2 MF capacitor after

Must have <2uf after... Thanks for the info, but a reason or reference would be much appreciated... surely larger is better? Or does a larger cap take longer to charge causing hysteresis?

xcien TommyT14 months ago


fr3dd410 months ago

Do you know of a way to stabilize at 5 volts output but having an input at 5 volts? When I put a load on, the voltage drops to 2 volts output.

TommyT1 fr3dd44 months ago

the 7805 is a voltage regulator it will "stabilise" an input voltage of 7-35DCv to a regulated 5DCv what happens after is your problem....

if your not meeting said requirements it will not work correctly.

heat, amperage and capacitance will also be a factor i like using a larger capacitor at the lead-in and smaller ceramic capacitors with the other circuit components.

srah1 fr3dd49 months ago

According to the datasheet for my 7805 regulator the recommended minimum input voltage is 7V. At an input of 5V the device is under-powered and not working efficiently so you're getting low voltages at the load. In other words, to stabilize the output at 5V you'll need to increase the input voltage. Also, if your input is a guaranteed 5V, perhaps you do not need even need a regulator.

Mr_MdR5 months ago


What happens to the output when the input voltage is 5v?

Mackmario made it!6 months ago

I made mine with the 0.1uf ceramic capacitor like you stated in one of the comments

nikodll8 months ago

I created a picture of how I'm wiring a LED and a resistor (see attached), but when I measure the voltage between points A and B, I see less than 5V. I suspect some current escapes through the 1uF capacitor. Could someone have a quick look if I should put the led+resistor on the orange line instead? Would that be the proper way to use capacitor for stabilization? Also, am I connecting the 10uF capacitor correctly, or it should be rather in series on the plus line or ground of the battery?


You are probably measuring around 2-3V right? This is because you are measuring the voltage across the LED, not the entire output. If you measured from Point A to the other side of the resistor (the end going to ground, or the negative side of the battery), you would then measure closer to 5V. The voltage regulator is outputting 5V. Some of it gets "used up" by the resistor, and some by the LED. Measure across the LED, then measure across the resistor. The two readings should add up to 5V, which should also be the same amount measured across the LED AND Resistor together.

claws11 year ago

Is there an alternative to the 1uF 25v capacitor? I am finding it extremely hard to find in the UK and don't wish to buy from China as the delivery will take too long. Would something like a 1uF 35v work? or something lower?

1uf 35V would work. The voltage ratings on capacitors indicate the maximum voltage that the capacitor can handle and thus a 35V capacitor instead of a 25V capacitor would work. Technically, a capacitor rated as low as 5V or 10V would still work. Also, the datasheet actually recommends using a 0.1uf (100nf) ceramic capacitor on the output and not a 1uf electrolytic capacitor.

Solar Dave1 year ago

I want to make a 5V charger for my old 6V Motorcycle (iPod, iPad, iPhone). My question is, Will the circuit work with a 6V input, and even though it is a DC to DC application, would a capacitor be useful in case there are spikes coming from the old voltage regulator?

Using a 6V power source for the LM7805 regulator will not work. LM7805's have a dropout voltage of 2V meaning that the input voltage must be at least 2V above it's output (5V + 2V = 7V Min). Attempting to use any voltage lower than 7V will yield a lower, unstable voltage (typically 2.0V - 4.5V).

As a side note, for all linear regulators, a higher difference between the input and output voltages will create more heat which can exceed 150 C.

jordanwade3 years ago
cant u just use a 7805 regulator?
yes the caps are for ac dc to dc just regulator is fine i hook up 2 100k ohm to my circuit to charge my iphone 4s off a dollar store 9v (will soon add a joule theft circuit)
GofishRC0072 years ago
Hey I got 3 of the L7805 and 2 are + and one is - will the - still work?
gungfudan2 years ago
would a 100-Ohm resistor work for the LED.
sooraj619 (author)  gungfudan2 years ago
a resistance greater than 330 ohm can be used for led 2.5v 20ma
thank you.
cubbydebry2 years ago
Thanks so much,
I needed this for a usb charger and had no idea where the capacitors were supposed to go
sooraj619 (author)  cubbydebry2 years ago
thank you
dosftw2 years ago
Have you used vero stripboard or dot matrix stripboard?
sooraj619 (author)  dosftw2 years ago
dot matrix stripboard
ecopp963 years ago
Estuve probando y tu sistema me lavantaba mucha temperatura y me genera mucho ruido termico. Por ende decidi probar y consegui una formula algo mas refinada usando c1= 2200 uf a 25v y c2=220uf a 25v
sooraj619 (author)  ecopp963 years ago
bien, ¿cómo?
pandyaketan3 years ago
Good work.

But if you make a diode bridge (see my IBles, by clicking my name on the left), you can use 220/110 V AC mains also to step it down to low voltage levels...

andy707073 years ago
The 7805 isn't a transistor. Also, the heatsink in the TO220 package is usually plenty, and as for the capacitors, smaller 100nF and 220nF non-polarised capacitors can be used instead.
ray_Bond3 years ago
first thing sooraj bhai its regulator not transistor second its rating is for max current of 1 amps ( at 25*C of temp. and proper heat sink ) and max input voltage 7.25v to 12v. no offense bhai par packing also plays role in amps rating.............:)
sooraj619 (author)  ray_Bond3 years ago
zack2473 years ago
i never used the capacitors before, how do they affect the performance of the 7805?
the capacitors reduce ac "ripples" from the dc current.
sooraj619 (author)  zack2473 years ago
it filters ripples from the input and gives a smooth output
Hi Zack

I am an *extreem* newbie, but the capacitors help smooth out or regulate the power supply so that you have less noise on your lines which can cause havoc with your digital signals.

I am sure a pro will chime in and give a clear and complete answer.
ghuebo3 years ago
Really good! that´s what I was looking for! but I've a question... I´m using a 12V 1A dc power supply and the L7805 is hot as hell! is this normal??
sooraj619 (author)  ghuebo3 years ago
yes, you may increase the size of the heat sink to reduce the heat
jordanwade3 years ago
but i use it for 9v to get 5v