555 DC Motor Speed Control


Introduction: 555 DC Motor Speed Control

About: Geophysicist, Paraglider, explorer, comes from the desert and loves the world and all science.

This is a pretty cool circuit that allows you to control the speed a DC motor of considerable size! This circuit was made as part of the Jameco and Instructables Hacknight Hosted by H3 Laboratories in El Paso Texas

Jameco sent us a grab bag of awesome components that we put into use right away!

Bill of Materials:

1 - 555 Timer IC (from Jameco)
2 - Small Glass Rectifier Diodes
1 - High Current Rectifier Diode (Jameco)
1 - 1MΩ Potentiometer (From Jameco)
1 - (Green, Red, Brown) Resistor
1 - 1KΩ (Brown, Black, Red) Resistor
1 - Power MOSFET
2 - .01 µF Ceramic Capacitors
1 - DC Motor

Step 1: Install Jumper Cables

We will be needing a lot of jumper cables. I tend to install them first and later put in the components but you can do it any way you want just follow the schematic. If you want, you can follow my way.

Install the 555 IC on the breadboard.

Step 2: More Jumpers

Install the other jumper that will be going to the potentiometer.

Step 3: Jumpers

More jumpers connecting pins 4 and 8 and 2 and 6

Step 4: Install the Two Capacitors .01µF and Diodes

Follow the picture

Step 5: Install the Remaining Components As Shown in the Picture

The circuit is finished follow the schematic for more clarification on the position of components.

Step 6: Video

Here we have a video demonstration of the circuit working:

This circuit was made as part of the Jameco and Instructables Hacknight Hosted by H3 Laboratories in El Paso Texas



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19 Discussions

thanks for sharing your project.

on which website can i find your type of breadboard?


1 year ago

Value of the potentiometer on the parts list is 1MΩ (=1000kΩ). Value of potentiometer in the schematic is 100kΩ. Will they both work?





2 years ago

Systematic diagram please...thanks

what is the useful of the capacitor parallel with irf520 and 2 parallel diodes on left ?

The capacitors on the schematic are totally different than in the circuit/parts list?

hey !!! what is that thing its looks like electrolytic caps if it what is the volt. and.... the farad of the caps ? pls pm i want to try

The schematic is correct. Pin 7 is equivalent to pin 3 but it does not go high. The circuit uses the gate of the MOSFET through pin 7, you can try it. It works

you need to correct the schematic. need to swap pin #'s for pin 3 and 7.

At the present I have no plans to use this circuit, but I appreciate what you have done. It is very practical.

Great project!
The 555 works like a PWM emitter doesn't it? With frequency adjusted by the potenciometer right?
I don't know the difference between a MOSFET and a Transistor. What is it?

Thanks in advance!

That depends on the MOSFET you are using, this one is the IRF640 can handle 18A @ 10V in 25°C you can use different MOSFETs and power supplies and the possibilities are even higher.

Yes, they are correct:

(Pins 7 and 3 are "in phase.") Pin 7 is equal to pin 3 but pin 7 does not go high - it goes OPEN. But it goes LOW and will sink about 200mA.



Are 3 and 7 from the 555 correct? Output = 3 an Discharge is 7.