# 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

## Step 1: 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

wires

common circuit board
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DrMaker12 days ago

Hi, there is a little mistake on the first image.

It says L7805 transistor and should be L7805 Voltage Regulator.

Grettings!

VandanaS123 days ago
larsje3902 months ago

Hello nice project, but I have one question

What happens when the original battery voltage drops below five volts? will it still output that lower voltage or nothing at all?

1 month ago

The voltage regulator doesn't work if the input is less than 6V (this value varies with the manufacturer) and can hold upto a maximum of 35V. But coming to your question, what will be the output if it is less 5V?

The voltage regulator, basically dissipates energy to achieve its function. And since the input is less than what is recommended, some energy is lost in its circuitry and the output is much less than the input. eg. if I give 5V to the input, some energy is lost inside and the output would be around 1.7-2V .

GuoJ2 months ago

hi what if i have a 24v and i want to convert it to 5v

sooraj619 (author)  GuoJ2 months ago

http://www.instructables.com/id/5V-2A-regulator/

SchwettyBawls3 months ago

I plan to make something like this to power a Raspberry Pi B+ in my car. What regulator would I need to supply 5v 2amp output. Sadly the L7805 just doesn't have the amps I need.

sooraj619 (author)  SchwettyBawls2 months ago

http://www.instructables.com/id/5V-2A-regulator/

Doc Cox 3 months ago

Thank you for this circuit, just what I was looking for to charge lithium batteries, regards Doc Cox

sooraj619 (author)  Doc Cox 2 months ago

:)

CongN13 months ago

Can i use it with a 12V-5A to step down for 5v-1A DC , 5A to 1A ? the power supply current can be affect or not ? i think i do affect , doesn''t it ? because i''ve alreay had a 12V-5A DC and want a 5V-1A for my device !

sooraj619 (author)  CongN12 months ago

the output from the circuit is 5v 1A. if you give 12-5A as input the heat sink size used for the 7805 IC should be increased as it gets more hot.

keesv12 months ago

Just let a volregulator drive a fet or and use a zener and a shunt resistor or better, just read the millions of articles about the most used voltage regular serie in the word, from 1976. But don't expect high end superstable low noise, low quiscent currents(warmth). This is the most standard 'schematic' possible and a filmcapacitor couldn't hurt neither then a cheap elco and you can never drive a voltage regulator like this one, with a lower input voltage then the output .They are not efficient and need power to maintain the output voltage and current. And switching 12 v 5a are more efficient parts for on the market, redcon makes good ones, but i think you mean that your powersupply is able to give max 5A , why would you else want 1A. analogue devices has a lot of articles (and very nice components) on their website.and the max amperes a 7805 can draw, i've seen was 2,5A , but the most 1 to 1,5 A With a coolblock. If you want more power and be able to adjust the adjust the output voltage take this one http://www.ti.com/lit/ds/symlink/lm350-n.pdf. with a lotttt of schematics, included formula.... goodluck

2015s1000rr3 months ago

I came here searching for an issue I am having with dashcam setup on my motorcycle. I connected the camera to a switched power source (accessory circuit that comes on when ignition turns on). My expectation is, when the bike is on, the camera would record, and when I turn the ignition off, the camera would turn off. The camera is configured to "record on power".

NiranjanS15 months ago

can i use this regulator to regulate 3v to 5v

4 months ago
Hi NiranjanS1. The regulator does not 'stepup' voltage. It's only used to regulate voltage downwards.
dubnikov5 months ago

And what maximum input voltage L7805 can handle?

Mërgim Halimi5 months ago

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 ?

5 months ago

HI, If you look at the link below you'll see a great write-up about this particular regulator. But for the short answer it will work but it'll throw out more heat. The closer the source voltage to the output the less heat there will be. Make sure you have adaquate cooling!

http://www.learningaboutelectronics.com/Articles/What-is-a-LM7805-voltage-regulator

xcien10 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

9 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

6 months ago

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?

9 months ago

Thanks.

fr3dd41 year 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.

9 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.

1 year 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. https://www.sparkfun.com/datasheets/Components/LM7805.pdf

Mr_MdR10 months ago

Hi!

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

Mackmario made it!11 months ago

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

nikodll1 year 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?

1 year ago

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?

1 year ago

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.

1 year ago
thanks.
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?

1 year ago

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.

jordanwade4 years ago
cant u just use a 7805 regulator?
2 years ago
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
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