er can anyone help me with joining the regulator diagram together with the motor to form 1 circuit diagram . thx This should do
and can anyone tell me why do i use a 47uF 25V capcitor in the regulator circuit ?
According to the datasheet, for input voltages of 32V and beyond, a 22µF cap is needed, but nothing is described for less than 32V.
However, it's a good idea to have a cap in front of a voltage regulator and more so when it's a switcher taking its power in pulses, as the battery might not be able to cope and the resistance of the leads from the battery will come more into play without it.
Normally, you'd have a cap on the output as well, but since I don't know what you're gonna load it with and since it has a limit of 470µF capacitive load, I haven't included one, but if you haven't got any capacity in the load, add between 10µF and 50µF as close to the output terminal as possible (to the ground plane), as this will reduce the output ripple (which can be up to 75mV in amplitude without a cap).
With a switcher (and anything that's electrically noisy), the capacitor should have the lowest possible ESR (Equivalent Series Resistance) and using 2 or 3 to sum up to the needed value gives a lower ESR (since each ones ESR is parallelled with the rest).
The coil L1 can be just about any coil with a good wrap of wire, the best will be powdered iron cores (yellow core) that you can find in abundance in broken PC power supplies. If you cannot find one, just use a piece of wire and live with the motor (electrical) noise remaining.