555 Blinking LED -- One cycle and stops

SgtWookie said:

Bill,
Your R3 is pretty small at only 10 Ohms. If pot R4 were adjusted near 0, with a 9v supply, you would have pretty high instantaneous current going through R3 (~600mA, or 2/3 Vcc / 10 Ohms) when the 555 output changes states. That could cause the failure of pot R4.

Changing C1 to 10uF, R4 to 100k and R3 to 100 Ohms would cut the instantaneous current to 60mA, the timing would be unchanged, and the capacitor would be smaller in physical size (if rated for the same voltage). Cap leakage could become more of an issue, but likely pretty inconsequential with fresh caps.

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