I couldn't make the LED blink building with my breadboard. So I tried out the experiment with an online simulator. The LED does not blink in the simulator as well. Is it because the simulator does not reflect the reality, or I connected it wrong? enter image description here enter image description here

  • \$\begingroup\$ Can you post the circuit diagram corresponding to the Make electronics article ? \$\endgroup\$
    – AJN
    Jul 23, 2020 at 7:39
  • \$\begingroup\$ @AJN You can find the diagram here: element14.com/community/thread/65453/l/… \$\endgroup\$
    – czheo
    Jul 23, 2020 at 7:43
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    \$\begingroup\$ Looks like the component values (in the simulator link) are different from the values in article link. 470 ohms seems like a very small resistance to connect from supply to base of the transistors. \$\endgroup\$
    – AJN
    Jul 23, 2020 at 7:46
  • \$\begingroup\$ I added 2 more zeros to the resistance value to the resistors marked 470 ohms. Now the LED blinks. \$\endgroup\$
    – AJN
    Jul 23, 2020 at 7:47
  • \$\begingroup\$ tinyurl.com/y4mvrome See this modified circuit. The 470 ohms resistors to BJT base is so small that both transistors are ON continuously even though the capacitors try to take away some current to switch the transistor OFF \$\endgroup\$
    – AJN
    Jul 23, 2020 at 7:49

1 Answer 1


The article has 470K resistors and you've used 470 ohm resistors, that's off by 1000:1 (too low). I can't really see what your values are on the breadboard.

The simulator may or may not work, oscillators sometimes need a bit of a whack to get going.

Edit: In this case, it does work when the resistor values are changed.


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