Two transistor circuit to pulse the output to a resistive load.
~500 ohms is suitable for a medium power led with a pulse time at 1Hz.
2.2 Ohm resistor, such as an incandescent bulb and 47uF and 470uF capacitor values will flash about 4Hz.
Higher resistance values on the output load slow the pulse time, so changes to resistance must be met with proper capacitor sizing.
