Xiaoyztan50 Pcs 160Ohm Passive Electronic Buzzers 3-5V DC 2-Terminal Mini Loudspeakers for Small Household Applicances

Another user, which looks like to be a college student, making a project with these passive speakers made a video to show the sound quality of the speakers. However, it’s highly incorrect. I don’t know if his video software helped the sound or what. What I can say is that they not like the video. These passive speakers are very quiet and hard to hear if you're more then a few feet away from them.

The impedance is about ten times lower. I get 20 ohms 6.8 millihenrys at 1 kHz.

So far, all of mine have worked fine when connected to an Arduino Nano Digital pin and used with the example sketch, "toneMelody.ino" that comes with the Arduino IDE. I did not use it with the 100 ohm current limiting resistor noted in the schematic that goes with the sketch. So far, I have tested about 6 or so, with no failures of any of the speakers, or the Nano itself. While its DC coil resistance is only about 16 ohms, I suspect its impedance when driven with the square or pulse wave from the Nano is the 160 ohms advertised.UPDATE: I just measured the AC impedance using the Arduino D8 pin and the tone() function. At audio frequencies it was about 200 ohms (frequency dependent). It appears that the advertised 160 ohms is correct. That SHOULD work on an Arduino with no problems. Keep the frequency above 260Hz. As you approach DC (f=0), the 16ohm resistance will be prevalent and you may destroy the output of your Arduino unless you use a current limiting resistor in series. Also consider using 2 of these in series. They are cheap. The volume doesn't seem to change, but the Arduino only needs to supply half the current, and it seems to sound better.

Playing around with an rp2040 micro controller, and needed a new passive speaker

product came sooner than expected. This is not self driven. It requires a driver circuit. it's basically a micro speaker with a magnet and coil driving a small metal disk.

The media could not be loaded.  Good value for an 18¢ speaker. I used the recommended driving circuit and it works great with plenty of volume. It’s ear piercingly loud at 2093Hz and plenty loud around 600Hz-1000Hz. Keep in mind that this definitely has a “buzzer” sound to it, not a nice “mini loudspeaker” sound. I imagine you could probably make it sound nicer with some low pass filtering.

Attached it to a board and it works.

They work. They're inexpensive. What more can be said!