PWM Module having Adjustable Frequency & Duty Cycle with LCD Display

A very low cost module (< $3) with excellent Features:

  • LCD display of frequency and duty cycle 
  • PWM output can be set to the specified frequency and duty cycle.
  • Wide frequency range with high accuracy;
  • Serial communication features, TTL level
Aliexpress Price

Parameter settings

The module has four independent buttons, used to set the frequency and duty cycle, momentary press (increase or decrease by a unit) and long press (fast increase or decrease). Parameters get automatically saved, even after switching off and then switching on.

PWM output, one can set frequency & duty cycle;

It has 4 Frequency ranges, automatic switching:

1   xxx (no decimal point): the smallest  is 1Hz, range  1Hz to 999Hz;

2   x.xx (decimal point at hundred) the smallest is 0.01Khz, trange of 1.00Khz to 9.99Khz;

3   xx.x (decimal at in ten): the smallest unit is 0.1Khz; value range of 10.0KHz ~ 99.9KHz

4   x.x.x (decimal at ten and hundred): the smallest  is 1Khz;  range 1KHz ~ 150KHz

5   Frequency display:

100 displayed= output 100Hz pulse;     1.01 displayed =output 1.01K pulse; 54.1 displayed = output  pulse of 54.1 kHz;

1.2.4 displayed = output 124 kHz pulse;

6   Duty cycle range: 0 to 100%;

7   All settings at power-down gets automatically saved.


  • Operating voltage: 3.3 ~ 30V;
  • Frequency range: 1Hz ~ 150KHz;
  • Frequency accuracy: 2%;
  • Signal loading capacity: output current from 5 to 30ma;
  • Output amplitude: Of PWM = supply voltage;
  • Ambient temperature: -20 to +70 degre c

Application Area:

  • For lab used as a square wave signal generator,
  • Can be used with transistor to control motor speed;
  • Gives adjustable pulse for Microcontroller use;
  • Delivers adjustable pulse, to get (PWM dimming and other applications).
  • serial control (single-chip TTL level communication)

Serial Communication standard:

9600 bps Data bits: 8

Stop bit: 1

Check digit: none

Flow control: none

  • Set the frequency of the PWM

“F101”: Set the frequency to 101 HZ (001 to 999)

“F1.05”: Set the frequency of 1.05 KHZ (1.00 to 9.99)

“F10.5”: Set the frequency to 10.5KHZ (10.0 to 99.9)

“F1.0.5”: set the frequency of 105KHZ (1.0.0 to 1.5.0)

  • Set the PWM duty cycle

“DXXX”: set the PWM duty cycle to XXX; (001 ~ 100)

Such as D050, set the PWM duty cycle is 50%

  • Reading the set parameters

Send a “read” string to read the set parameters.

Set successfully return: DOWN;

Setup failed to return: FALL.

Module Image credit

Written by 

Advisor on electronics electrical hardware

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