“In this Instructable I show you how to make a simple LED chaser circuit. The special thing about this circuit is that it does not use an IC (Integrated Circuit).
By using different resistors, capacitors and transistors, I succeeded in this project to make a circuit that lights the LED lights one by one. The base of both the transistors are connected to + connection through resistor. Any one transistor will get activated first. (this is because no transistor is exactly similar to other one). Lets assume transistor 1 turns on first. When the transistor turns on the collector pin gets grounded and led at its collector lights up. Also the capacitor starts to charge through ground provided by 1st transistor and the 4.7 K resistor at the base of 2nd transistor. Since the 1st capacitor is charging it is taking current from the 4.7 K resistor which is at the base of 2nd transistor. The base of 2nd transistor has no current to activate its led. At some point 1st capacitor will charge up. And when it does so, there is no more current flowing through it. Now there is enough current that can flow through base of 2nd transistor. The 2nd transistor gets activated. (Including the led connected to its collector). The process repeats and when the 2nd capacitor is charged the third transistor is activated. Then the first, second and so on.
3 x 3 LED lights (any color you want)
3 BC547 transistors
3 330 Ohm resistors
3 4.7 K resistors
3 100 uF capacitors
Electrical wire (small pieces)”