A very simple boost converter circuit can be built by using a handful of transistors and some passive electronic components for boosting any low voltage to the desired high voltage level.
The shown boost converter circuit is simple with its topology since it works with a couple of standard circuits stages involving an transistorized astable stage and a boost converter stage.
The astable stage is formed by the two BC548 transistors and the associated resistors and capacitors. The involved two capacitors and the two base resistors determine the frequency of the astable
This frequency is fed to the gate of a mosfet which is rigged as a boost converter in conjunction with its drain inductor.
The astable frequency drives the mosfet and inductor at the specified frequency causing a much higher stepped up voltage to develop across the drain and source of the mosfet.
This boosted voltage is collected across the 1000uF filter capacitor after appropriately rectifying it via the 1N4007 diode.
The number of turns on the coil could be equal to the supply voltgae level, here it's around 12 turns, diameter could be around 20mm. The core should be a ferrite material.
The feedback BC548 makes sure that ther boost volatge should not increase above 24V which is determined by the 24V zener diode.
This implies thsat the proposed simple boost converter circuit output could be dimensioned as per user's choice simply by increasing the number of turns and/or by altering the value of the 24V zener diode.