Review on Controller DROK Regulator Governor Modulator by Hector Liamsi

Make no mistake, this is a relatively cheap piece of equipment in terms of quality. It's good enough for my needs though, as I've used it as a speed controller for some of the DC fans in my apartment. Note that when driving an inductive load like a motor you will hear a fairly loud howl when the regulator is in the 10-90% range. ---- BUILD QUALITY ---- The aluminum heatsink is bolted directly to the board to dissipate heat, although it's the wrong size and barely covers the latest driver chip. However, this did not appear to be a problem in the test, as the manufacturer used thermal paste on all contact surfaces. Also unsurprising was the use of an unbranded filter cover with long leads that wasn't glued or otherwise attached to the board. All of this means that THIS DEVICE SHOULD NOT BE USED FOR CRITICAL APPLICATIONS OR APPLICATIONS RELATED TO MECHANICAL SHOCK OR VIBRATIONS. burn down my apartment. ---- LOAD TEST (see attached photos) ---- PSU: Korad KA3005PO Oscilloscope: HP 54603BMMultimeter: Radio Shack 22-813 (hey, it tests continuity faster than my Extech!) Thermal Imager: FLIR One for Android. The power supply consisted of a linear power supply configured for 24V and the load consisted of two 12V DC fans connected in series. It is important to note that the negative power and load terminals are NOT common (shorted) and during testing ranged from 12V to several millivolts relative voltages. During my testing, the PWM frequency was around 15kHz and when running with an inductive test load (DC fan) showed a noticeable "ringing” on the trailing edge of the signal. In fact, there was so much ringing that my oscilloscope struggled to trigger the signal consistently, let alone extract constant duty cycle values. The thermal camera showed that the part that receives the most is the PWM signal conditioner. The peak temperature during normal operation was 40.5°C. I forgot to put the part number on this chip but would be happy to post it here if requested. ----TL; DR ---- This is a $12 PWM controller. You get what you pay for. It's both inexpensive and a cheap little device, but it's perfectly fine for smaller projects.