In article , "Rightrik" wrote:

Hello, i need a little, low power (about 500 mA) step up converter from 12 v
dc to 24 v dc to operate correctly a 4 ways coaxial switch.
I have found project on the net, but i wonder if there is a ready, little,
not ott expensive kit or ready-to-go-module to obtain this 24-26 v dc
voltage from 12 (13,8) dc volt input.

Riccardo-

If you have a 12 volt inverter of any kind, you might look at the primary
side of its circuit. If the transformer center tap is connected to 12
volts and it uses switching transistors to alternately connect the ends of
a transformer winding to ground, then you can connect rectifiers from the
ends of the transformer winding, to a filter capacitor for a plus 24 volt
supply.

When one end is grounded, the center is still plus 12 volts, so the
opposite end of the winding becomes plus 24.

73, Fred, K4DII