The stepper motor is a DC motor that moves in discrete steps .It is often used in printers and even robotics .
I will explain this circuit in steps .
The first part of the circuit is a 555 timer. It is the first image(see above) with a 555 chip with part of the screen of an oscilloscope .
The 555 timer has many uses it can be used as an alarm,but most frequently it is used in digital circuits as a clock . A clock functions to give a pulsed input to a digital circuit .It can turn off and on digital circuit
(as D flip flops ). The frequency of these pulsed output of the clock are fast and can measured with an oscilloscope .In the second image you can see a part of a square which is part of an output from the clock.
The part needed to build the 555 timer are;
1k resistor (colors brown,black, red)
10k resistor (colors brown ,black ,orange)
100 k potentiometer
10uf capacitor (electrolytic);the large capacitor there
0.1 uf capacitor ;the small capacitor there
4.7 k resistor)color yellow,purple and red)
Step 1: The D Flip Flop
The next part of the circuit is the D flip flop and motor. See image two .The D flip flop the the long chip with the number 74 HC 74 .A D flip flop is used in many digital circuits.It's output will vary according to the clock input .
It turns on and off according to the frequency of the clock. In this circuit the D flip flip is a driver for the stepper motor . So another part needed is a D flip flop;74HC74 If you look at image 2 you with see these connections in the circuits. The clock,Pin 3 (output), of the 555 timer is connected to 74HC74(D flip flop IC) to pin 3(purple lead) .The D input(pin 2) goes to pin 6 which is Q(not) .( Yellow lead) The second D input is connected to the second Q (not).(pin 12 to 8).(yellow lead).The diagonal purple lead connects Q to the second clock.
Step 2: How the Circuit Works
The circuit consists of a 555 timer with D Flip flops and stepper motor and 9 volt battery.
The 555 timer is the clock and help the D flip flop turn on and off (pulsed output). The clock also pulses the stepper motor. The D flip flip is another driver for the stepper motor . The 9 volt battery(DC source) is attached directly to the input of the stepper motor. The Arduino provides 5 volt (see image)
Step 3: The Stepper Motor
The last part of the circuit is the stepper motor.
The red and black leads are connected to the 9 volt battery.The blue and yellow leads are connected to the D flip flops .(as in the image 1) The last part needed ; a stepper motor and Arduino .The Arduino provides a 5 volt input .(See image)T.he stepper is running at 116 rpms .It is set at 165 rpms .The efficiency of the motor is 116/165 or 70 %
I designed this circuit on Tinkercad .
It works .I enjoyed this project
.I hope it helps you understand stepper motor s better