light emitting diode control differ controls

[venkates2218]

in this image i used two PNP transistor along with NPN to control the power supply to LED...
On one hand power will directly given to LED when PNP transister is switched on by NPN transistor...

On other hand I used same switching principle but switching NPN by using PWM to dim and bright the LED...

Is this circuit is correct the LED will work on both power supply and PWM input..?
Or i have to change anything in this circuit..?

 

[Easyrider83]

Before you will damage the transistors, please, read some books about electronic basics. To open the transistor you have to apply the current to it base, not voltage. It is bipolar transistor, not FET.
Anyway, compare to Okado, no one will be injured this time hopefully. :-D
Yes, this will work if you will add resistors to limit the current.

 

[venkates2218]

:lol::lol: ok easyrider83 thanks..


now it is ok..?

 

[KlausST]

Hi,

No, LEDs need a current limiting resistor, too.

Klaus

 

[venkates2218]

Ok Klausst i will change it..
Remaining every thing is ok..?
Led will wok under PWM waveforum..?

 

[Easyrider83]

It is just simple logic OR. Led will glow when one of the side transistors will be opened.

 

[venkates2218]

LED will glow based on PWM also..?

 

[Allen6502]

What if both the switch and the PWM are ON?

 

[venkates2218]

only when the pwm switch is ON means(at this condition another switch in open condition)

LED have to work ON PWM wavelength

 

[Okada]

PWM LED project will not work on Proteus. You will see only LED flickering. In hardware it will work then brightness. I have to test proteus simulation with Core i7 Extreme system.

 

[venkates2218]

ok OKADA
This circuit is correct for real time hardware operation..?

 

[Okada]

Remove connection between LED1 and LED2 anodes.

Add 330E between Collector and Anode of LEDs.

Then it will be ok for testing on hardware.

 

[venkates2218]

I'm going to use induction bulb it will take 12v/6W power...
CK100 is suitable for it..?

The Bulb will blink frequently during running condition..?
Does transistor will failure for this operation..?

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if i used two transistor on both side of bulb means load current will shared on each other or load will shared on positive side only

 

[Okada]

Use 2A transistor.

I = 6W/12 = 500 mA

Transistor will be warm at this current if 2N2222A is used or BC337 is used.

 

[venkates2218]

in positive side i used pnp transistor(2A range) to control positive supply to bulb and if i need to control negative to bulb also means i have to use same range of transistor or basic transistor like BC547 can use..?

 

[Okada]

What is positive and negative side in a bulb ?

 

[venkates2218]

no it not having any negative or positive polarity we can give supply in any type.
it going to work in 12V dc battery so their will be both positive and negative polarity i'm mentioning that..
But i need to control both positive and negative to bulb means we can use high collector current rating transistor in positive side from power supply and low collector current rating transistor in negative side from power supply

 

[Okada]

All you need is a transistor switch. Check the TIP39 or TIP49 datasheet. You know mac collector current and from datasheet you will get beta or use multimeter to check the beta of transistor. Decide base current required and accordingly choose base resistor.

 

[venkates2218]

please check CK100 transistor i think it having capacity of 1A collector current....

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in our market i can't get rare components...so i need to use what available in market only...

 

[Okada]

Ic = BIb

datasheet tells that

Ic = 150 mA with Ib = 15 mA

So, B = 150 / 15 = 10

Your Ic = 6W/12 = 500 mA, take it as 600 mA

So, Ib = Ic/B = 600 mA / 10 = 60 mA

MCU pin voltage is 5V, Vbe = 0.7V, Ib = 60 mA

So, (V - Vbe) / Ib =

5 - 0.7 / 60 = 71.67E

choose 69E for base resistor

.. 2N2222A is available in India.