İKİ TRANSİSTÖRLÜ LED
R1,R4 = 470, 5%
R2,R3 = 39K, 5%
C1,C2 = 10µF/16V
Q1,Q2 = 2N3904
Led's = High Brightness, Red
Classic astable multivibrator using 2 transistors. Transistor is not critical.
Try these: 2N4401, 2N2222, NTE123A, NTE123AP, NTE159, TUP/TUN and those in your
junk box, you may find that most of them will work.
Obviously, the 470 ohm resistor determines the LED's brightness and limits the
current flow to about 20mA. 390 ohm can also be used as a save value. If you
decide to go with a green or yellow led, which draw more current, you may want
to replace the 470 ohm with 270 or 330 ohm values. Flash rate is determined by
the 39K resistors and the 10µF capacitors (determines the 'ON' time).
The two sides do not have to match. Different values for each side can give a
nice effect for unique duty-cycles. Flashrate for above circuit is 1 cycle per
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