A 12 to 24 volt converter can be built using simple electronic diagram below. This consists mainly of convetor just from a CMOS astabil multivibrator with a power output. When the bottom FET drive first electrolytic capacitor is charging. After this, the upper FET drive, it goes down in blocking state. Negative terminal of the first electrolytic capacitor is now found at 12 V, positive terminal, in contrast, is at a higher voltage 12 V, ie at 24 V. This voltage reaches a diode to the output electrolytic capacitor, which stores output voltage during charging the first capacitor.