* Flashing frequency can be varied by changing R1 value in the 1M - 4M7 range.
* This circuit is very efficient when driving a small 3.2V incandescent lamp. In this case omit the LED and R3, connecting the bulb across Q2 Collector and positive supply, further reducing parts counting.
* Maximum current drawing of the bulb type used should not exceed 100mA.
* In order to facilitate oscillation when a bulb is driven, R2 value should be lowered to 82R or 68R.