IC1: 555 Timer IC
T1: MJE 340
D1: 1N4004 or similar
This circuit works by collapsing a magnetic field in a small coil to induce high voltage spikes. The spikes are then fed through a diode to the output. The output cannot sustain anymore than 300V since this is the highest voltage the transistor will handle across the collector and emitter.
I have not yet worked out the most efficient on-time for the coil so you are welcome to experiment with R1, R2 and C1.
This circuit is ideal for strobe light applications.
I have not yet performed any tests since i am still experimenting with different value parts.
I can say that i got it to run at about 500mA and it charged a 10uF capacitor fast enough to strike a flash tube several times a second.