Make Electronics-Ex 11a

A couple of diodes help square up the oscillations a bit, they do require that slightly smaller biasing resistors be used. http://everycircuit.com/circuit/6213568111050752

Thanks. Yes, I saw how people use diodes to make the oscillation more square but to be honest this is a bit ahead of my very basic learning curve. The one thing I was wondering about is when current flows through the left hand-side 4.7K resistor and through the transistor directly below that, why there is no current flowing through the 100k resistor and to the base of the left-most transistor thereby allowing current to flow through to the LED. I know that if it was the case then the LED would be ON all the time but I am not sure I understand why the current could not theoretically flow through there as well.

I've removed the diodes, and high lighted the base voltage, you really need to understand how the circuit biasing works. http://everycircuit.com/circuit/6213568111050752

Ok I found my answer. Current does flow through the left-most transistor when the LED is OFF. It is just that it is not enough even with the amplification of the transistor to turn the LED ON. If I lower the value of the left-most 4.7K ohms resistor and get more current to flow through that transistor, then the LED stays on all the time (with a flicker in between).