100W OU Radiant Energy Circuit

[JoeLag]

I have managed to find the problem. It was a wrong connection on the breadboard. Now it oscillates with a backward-connected transistor (without the base, which in my case is a 15 V threshold) or with a Zenner diode (5 V) at 50% duty cycle at the 5 MHz range. The DC power supply shows 5 V at 20 mA which means it eats all the current I'm giving it.

BTW: Is it possible to create an oscillator with a short duty cycle without using a 555 timer or any other IC component? Just basic components. I don't think the flyback oscillator circuits use a short duty cycle, because they oscillate, they don't create pulses.
(end of BTW)

Maybe you can use a transistor astable multivibrator circuit. This circuit uses two transistors (Q1 and Q2) to create an oscillation.
To achieve a short duty cycle, you can increase  and decrease the value of Rs. You can also increase and decrease the values of Cs. These changes will result in a shorter on-time and a longer off-time, which will give you a shorter duty cycle. Maybe look online for a basic circuit diagram and play with the values.