Product was successfully added to your shopping cart.

Go to cart page

You have successfully subscribed to this product. You will receive an email when the product is in stock.

Dc to pulse width modulator

Velleman K8004: Pulse Width Modulator Kit

Velleman K8004

The Velleman K8004 DC to Pulse Width Modulator

The K8004 converts your DC input voltage into a duty cycle (or set of pulses) that is proportionate to the DC voltage. Use the pulse modulator to control the speed of your motor, lights, or small heaters. Swap between three presets (RV1, RV2, RV3) on the board for varying applications. PWM ranges from 0 to 100% with adjustable frequency of 100 to 5000 Hz.


Use of this Velleman modulator will allow more efficient control of motors, lights, and heaters; the K8004 has more than 90% efficiency at full load. When using this board, you will have next to no loss of power when controlling your devices. The K8004 is protected from overload and short circuit.  

K8004 schematic diagram from Velleman

The K8004 is a kit and requires assembly. You will need a soldering iron and intermediate experience with kit assembly. 
For tailored control voltage, view the different configurations outlined in the Velleman assembly manual under the "Downloads" tab.

Schematic diagram of circuits shown.



  • Minimum PWM offset: 0–20 % adjustable
  • Adjustable Sensitivity: 2.5 to 35V DC
  • Overload Protection: 6.5A



  • Power Supply: 8 to 35V DC
  • Supply Current (no load): 35mA
  • Maximum Output Current: 6.5A
  • Dimensions: 3.4 x 1.9 x 1.8"


Additional Information

Difficulty Level 3


Parts list
English assembly instructions through illustrations, pictures, etc.

Assembly instructions
Written multilingual manual explaining how to build the kit

Info Sheets

Resistor colour code

Connection diagram with internal reference voltage

Connection diagram with modulator (with analogue output)

Overview of Velleman modules that are equal to D.I.Y Kits
This sheet is useful when you want to know which modules you could find in the do-it-yourself range of Velleman Kits and minikits.

Connection diagram using a seperate control voltage

 Warning: this product can expose you to chemicals which are known to the State of California to cause cancer, birth defects or other reproductive harm. For more information go to: www.P65Warnings.ca.gov/product