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# Simple LED Circuit

Some LED circuits explained examples from various projects: flashing LEDs, 220V LEDs and more.
We start by showing you the LED circuit in series with a resistor. You must make some calculations to figure out the resistor value, depending on voltage power supply, LED voltage drop and desired current.

Series LED circuit

(Source Voltage – LED Voltage Drop) / Amps = OHMs
Amps = mA/1000

Example:
Source Voltage = 9 volts
Voltage Drop = 3.1 volts typical for a blue or white LED
Desired Current = 13 milliamps

So the resistor we need is: (9 – 3.1) / ( 13 / 1000 ) = 452 ohms so we will use a 470 Ω resistor.

### 220 volt LED circuit

Caution: Do not try this circuit unless you have good knowledge about electronic devices. This circuit is connected to main power source (220V) and can give you a high electrical shock

We use one capacitor, a zener diode, a resistor and the LED.
The capacitors value depend on LED current. With a 100 nF capacitor, the LED current is 4 mA; at 470 nF the current is 20 mA.

Some LED flasher circuits

##### Related Tutorials

• Mg Khant Zaw Phyoe

Very nice.It is very useful for me.

• sunil

i am working on a led project but i dont know about led power.
i have 100 led bulb of 0.5 watt, i want connect all with power which is use at home.
can u tell me what type of “resister” use in project…?

• Dan Born

Great circuit, but what if you’re across the pond and working from 120v instead of 230? What values would change?

• Richard Knight

Great practical circuits that easy to understand and construct

• nikelillo

KDS,
when the current goes way down, (zener in inverse polarity) he keeps constant the voltaje between his terminals (2 volts in the picture) and all the current goes through the LED

if it goes in the other way, zener diode is in direct polarity and all the current goes through him protecting the LED which is in inverse polarity.

Please, forgive my english…

• KDS

what does the zener diode do?

• NIRAJ PAREKH

SOLAR SISTEM IN USE AND HOME LED LIGHT YOUR GIDE

• arun sharma

so good

• usman

wat is the size of led used in that circuit of 9 v

• johnny

Hey Guys
What brings me to your forum is a problem I’m half Mohegan Indian here in Ct . We are having problems with 2 stray dogs constantly on our propery and a stray wolf and bad neighbor with dog that are always on our property my daughter is in danger. I do not wish to put up a fence also no effective police nor health dept.. I wish to aquire or have build a powerful outdoor ultrisonic system , Ive built and fabricated mickey mouse internet sonic systems with no effect. IF this is something someone could build for us. I’am willing to pay upfront for parts and labor and after testing success another dozen units. I can also offer a free stay@ Mohegan sun resort and any free concerts for anyone who is knowledgable to build such a unit.. My family thanks you for anyhelp that you might provide..

thanks
johnny
off2timbuktu@yahoo.com

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