2pcs Signal Generator XY-KPWM 1-Channel 1Hz-150KHz PWM Pulse Frequency Generator DC 3.3V-30V 5-30mA Function Generator Duty Cycle Square Wave Generator Adjustable Module LCD Display

Used to control a DC motor with a third yellow wire. LEVOIT LV-PUR131 HEPA filters have controls and 'time to change filter' logic and ultimately will stop functioning. The HEPA filter unit is good, and the motor is fine. The fix is to use this unit to control the motor directly bypassing all the built in wiring. Add 24v DC power supply(20w). Hook the power + from the power supply to the motor red, and the volt + on the unit. Hook the black - from the power supply to the motor black, the volt - and PWM - on the unit. Hook the yellow from the motor to the PMW + on the unit. Will control the motor from 1-100%. I set the frequency to 20KHz

using this to generate signal to control a PWM radiator fan, works perfectly well in my application, i have constant 12v running to it, ground is hooked up to a thermal switch which turns this unit on at certain temperature, which in turn sends signal to the fan

It's working like should.

Item only has 4 connections. Ground, + battery, - battery, and a pcm( brown wire on alternator, [ excite wire] ). Pretty straight forward install. No power and unit does not work. Not sure why and just to clarify i search for online videos. None found. I just passed the return date so i lose my money. What a waste. Maybe a video installation attcahed to the product will help future buyers...