Controller Circuit

Diagrams picture

At picture is only be presented one parts to control one fruit of motor bobbin stepper. There is two alternatives that is by using former buffer or applies FET, what has a real input impedance height, as the switches component. Tension V motor is not must always equal to tension VCC at microcontroller. On that account applied by a buffer component having output open collector so that the output earns in pull-up to tension wanted.

For election base of the transistor is at characteristic IC (collector current). This transistor must be transistor power capable to overcome current as according to current required by this stepper motor bobbin. If current pulled by motor bobbin stepper simply bigger than abilities of transistor hence transistor would quickly hot and can cause the breakdown the transistor.

R pull-up 470 will give current 10 mA to transistor bases Q1. If Q1 had gain 1000 hence current which can be via is around some amperes, depended from big of current pulled by stepper motor bobbin. This current have to be more be small from current IC enabled.

For component FET can be applied component IRL540 which can flow current to 20 Ampere and can arrest back tension until 100V. This thing because of by this FET can permeate tension spike without protection of diode. But this component requires heat sink which is big and must be good enough in the case of absorbs of the temperature. It is better if it is applied capacitor to depress level tension spike generated from transition of switches from on to OFF.