Fantastic Atom Expander

Here is the schematic, PC board pattern, and parts placement for a
“Fantastic Atom Expander”. This circuit produces an “exploding atom”
effect using 98 LEDs.


This is the schematic of the Fantastic Atom Expander

PC Board Layout

This is the printed circuit layout for the Fantastic Atom Expander

Parts Placement

This is the parts placement for the Fantastic Atom Expander


Total Qty.
C1 1 0.1uf Mylar Capacitor 0.1uF Ceramic Disc Capacitor
IC1 1 4017 IC
IC2 1 555 Timer IC
L1-L98 98 Jumbo LED (any colour but blue)
Q1-Q5 5 2N3904 NPN Transistor
R1 1 4.7k Resistor
R2 1 680k Resistor
R3-R7 4 470 Ohm Resistor
MISC 1 PC Board, 9V Battery Snap, IC Sockets


  1. The LEDs can be any colour but blue. For a very interesting
    effect, make one ring red, the next one green, the next one orange, then
    yellow, etc.
  2. The transistors can be most any inexpensive NPN transistor (2N2222, PN2222A, Etc.).
  3. For a very interesting (and expensive!) effect, replace the
    2N3904’s with 2N3055 power transistors on heatsinks and use 12 V 500ma
    incandescent bulbs instead of LEDs.

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