I found the account

I found the account!
I can post about teaching electronics.
I had started this effort to teach, then my apartment of 17 years was stolen from me.
My new apartment is good, but better ? I don't know.
What is good? What is good is teaching knowledge to the next generation coming up.

The 3 LED circuit mobius band

Note The LED in the circuit diagram are "backward", the current flows through the 1k (or 333 Ohm) resistor and LED


Youtube video

The 3 LED circuit mobius band/ sequencer

Circuit Explanation
There are three(3) LEDS in the circuit.
Two transistors are "on", one transistor off.
The two transistors that are turned on, short out the LED associated with it.
The one transistor that is "off" lets that LED light, because there is a different of voltage between the connection of the LED.

The three capacitors (depending on the resistor that goes with it) individually charge "up". When fully charged the capacitor turns on the transistor that is attached directly to one of its leads. ( I don't fully understand this)

Parts List
Wire, breadboard/experimenting board.
3) 1K ohm
3) 27K ohm
3) NPN transistors (or PNP if you are knowledgable can reverse some voltages around)
3) 100 uF caps
3) LEDS
Power 6 to 15 volts, go with a 9 volt battery.
(If you go with higher voltage than 9Vdc, you will have to increase the resistance on the resistors that control the voltage flow through the LEDs.)


Using a plain dollar store 9 volt battery, you can play farely safely with changing various resistors in the circuit.

The circuit is a strange one , as during my experimentation, when I increased resistor resistance and expected a slower sequence, it did not happen. All parts of the circuit interact with each other to form the result.

You can try increasing and decreaseing the value of the capacitors.

IMPORTANT the 1K resistor (I suggest) can not be lower than 300 Ohms. If it is, the voltage and current will break the transistor and LED that tap off of it.

For near perfect timing of LEDs, keep all caps and resistors the same. BUT it is possibile to slightly change caps and resistors to produce a non 33/33/33 ratio to say 40/40/20.

NOTE 1:
In the video on youtube of my 3 LED chaser, I have a cheat. My circuit was not balanced enough or something. My problem was it would not start to oscillate and sequence once it had power. This was due I believe to too high a voltage/current loss.
The solution was to put a short circuit across one ( any one) of the LEDs for a split second using a switch . (momentary on switch) You can use a wire during testing.
The circuit would then start to go.

NOTE 2:
This circuits foundation comes from a two circuit oscillator. I tried extrapolating the principal to a FOUR LED chaser, but it does not work. What happens is the circuit turns into the two circuit oscillating model.

NOTE 3:
This circuit wastes power in that two transistors are letting voltage go through without producing anything , so this circuit is NOT recommended for a battery source and long life expectancy . Only powered locations should use this circuit in long term use. It may be possible to remake this circuit so its three sequence logic steps work at relatively low power usage, then buffer the three stages to a light display for a long life battery display.

First post

First post