DROK 5-30mA Signal Generator

Worked perfectly to modulate the Mercedes electric fan I installed on my Jeep.

This is a nice little budget-friendly frequency source. Reasonably low frequency drift, and low noise content on the square wave output these work great for operational burn-in testing in my test lab at work. If it could adjust the frequency in 0.1Hz increments it would have been a full 5 stars.

The user interface took a little time to master, but it's intuitive once you have spent a a few minutes on it. The higher accuracy mode (0.1% steps) worked well with the motor I used that required very-low RPM values (0.1% to 2.9% settings). Also good that the box retains the last setting prior to power off and and back on. I'll design something that has higher accuracy for my final product, but this was great for my customer demo and lab testing.

If you are looking for a basic speed controller to run brushless fans on a automotive project. This simple one dial controller work great. Easy to use and wire up. Cheap and work perfectly. And the best part is when the box is disconnected from power and reconnect it, it remembers your last setting to set you fan speed and leave it till you need it. I cruise around town with a 462 cammed BBC at 40% fan speed. with the AC cranked in 98 degree wether in traffic. Dial it up to 70% and works great

Worked perfectly. Modified its output stage and wrapped some other circuitry around it to create a J1772 Control Pilot signal generator for EMC testing at a publicly traded electric vehicle manufacturer. In a judo move that usually works against Murphy's law, I bought 2 or 3 of these, to guarantee the first one would work right, never break, and never get lost.

My biggest gripe is how difficult it is to insert the wires into the terminals when they’re inside a tight fitting box. Looking at the similar pwm generators on Amazon, this terminal is a common one so it’s probably not going to be a better on a different brand. Along the same lines, you’ll want to make sure your vertical opening is big enough to allow space for the wires/lugs to fit too otherwise it wont fit. I wish it was designed a bit better so there wasn’t such an opportunity for this vertical slop since once it makes it past the wires, there’s no more need for that extra space and your generator may slide up and down a bit while using it. Function wise, it seems to work well. I’m using it to drive the motor on my wife’s bricked “smart” treadmill. Since this thing outputs the same voltage as whatever it’s being fed, I used a 12v to 5v buck converter to lower the input voltage to a nice stable 5vdc. I like that it remembers the last settings so she doesn’t have to fiddle with setting the frequency each time. The only potential issue I made her away of is if the power goes out and she’s full bore on the thing, then it will go back to full bore when the power comes back on. Luckily during testing, our treadmill’s controller won’t start the more unless the controller first sees a duty of 0%, so that situation of it starting back up is mitigated but yours may not be, so I’d suggest testing it’s behavior beforehand.

Product came with a broken housing so you couldn’t push in the button without the module dismounting. Module seems to be made very cheap with poor quality control on their soldering to circuit board as well. Don’t want to have to return it and was not able to get through to their support.

They work, and they're cheap. I did have the output on one fail, but it may have been due to the user, it was on a PCB test rig. Maybe add a series resistor suitable to your application, and some clamp diodes.

El vendedor cumplio lo comprometido en su oferta y el elemento electronico esta funcionando correctamente, de igual forma fue entregado muy en tiempo.

Very easy to use device

Worked as described, set to 128Hz and produced 127Hz with a 5V feed wire. Used on electronically controlled alternator, works perfect for setting voltage via duty cycle. 10/10 would buy again.

The case of it was broken when showed up but still worked and did its job of testing gauges on Volkswagen gauge cluster.

This frequency generator is very poor quality. The plastic screen sheild keeps falling out of place, it has lamination issues also so it looks really ugly, and the programming is impossible, the functions don't work as described in the photos online, mind you there are no instructions and the online instruction is so poor that it might as well be written in Chinese.