This simple led flasher blinker circuit made by using two npn bc547 transistor and some resistors and capacitors.
2 transistor flasher circuit.
This is also called a free running multivibrator.
More about metsfan1938 how to make a circuit to make two leds flash back and forth.
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The resistor r and capacitor c determines the timing of the flasher and the period is proportional to r c.
We call it astable multivibrator.
Often we know it 2 led flasher circuit in this we use pnp transistor.
While today most people use a ne555 timer ic this version is simple to build.
I like blinking 2 led circuit using npn transistors.
This led flasher circuit is very easy and simple and there is no ic used.
Two transistor led flasher circuit.
In the second circuit a power fet is used in place of the npn.
This circuit uses a bc557 pnp transistor connected to a bc547 npn transistor in such a way so that the bc547 conducts for a very brief time making the led light.
Can be used on roads for signaling purposes.
The capacitor c charges through the resistor r and since its value is.
The two circuits below are typical connections.
The transistors do not necessarily have to be bc547 you may use 2n2222 or similar small signal transistors but it is recommended to always use the equivalent transistors.
Electrolytic capacitors 16v or more try using 47uf or 33uf capacitors to speed up the rate at which the leds flash.
The circuit will operate using almost any small npn transistors e g.
Simple 2 transistor led flasher circuit.
But now we use 2 npn transistor.
Ksp2222 pn2222 2n2222 bc107 bc108 bc109 etc.
We can create a dancing led circuit by combining many similar circuits which we can use for advertisement boards.
Blinking 2 led circuit using npn transistors.
Led flasher circuit diagram.
Npn transistors 2n2222 bc107 bc108 or bc109 transistors can be used in the circuit but have a different case to.
2 led flasher circuit simple blinking flasher led circuit.
470 ohm resistors yellow violet brown r1 r4.
The leds altering on off cycle whose flash rate is control by the two 22uf capacitors and the two 10k resistors.
The circuit can operate from a voltage of about 5v up to 12v change the value r4 to about 1k if using a voltage higher than around 10v.
Here is a blast from past as they say with a transistor astable multivibrator.
The speed of blinking can be changed by changing the value of capacitor c1 and c2.
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Power transistors may be added for handling higher current loads.
