5PCS DC5-15V 4.2V V-PP to 11.4V V-PP NE555 Pulse Frequency Duty Cycle Adjustable Generator Module Square Wave Rectangular Wave Signal Generator

If you can accept the limitations of the NE555 IC used, then this is a great little product. I suggest downloading the 555 datasheet from the web as a guide. Approximate frequencies are as follows (when set to about a 50% duty cycle):Jumper position 1: 1Hz-54Hz; 2: 120Hz-530 Hz; 3: 760 Hz-4800Hz; 4: 60kHz-250kHz. 2 * 10 turn trimmers set the frequency and duty cycle. Yes, they interact, so setting an exact frequency & duty cycle require a little patience. Two mounting holes are provided. A 3-pin header is used for DC in and signal out. Frequency range capacitors are 0603, so if you need an in between range, and have SMD tools, they can be changed. These frequencies were measured at 9V, no load. The frequencies will change under load and voltage. If you want some precision, I'd recommend a regulator like a 78L09 and good capacitor bypassing.

In my lab, students use 555 timers to make pulse generators. These small pre-assembled kits allow the 555 timers to perform like a pulse generator. So now you can easily make pulse generators of different periods by adjusting the trim pots on the board. You will need a DC power supply or small battery pack ( say 4.5 or perhaps 6.0 volts DC ) to operate the timer. You might need an oscilloscope to study the output signal or maybe a small amplifier to a speaker to listen to your signal - that is somewhat modified ( in signal shape ) by the speaker loading.

These simple 555 units have saved me time.A great value and perfect for my application into a higher voltage unit using a SSR.Versatile and easy to modify as I did.

The adjustable 555 timer module worked well for my project.I used it to generate a pulse to simulate the safety module pulse for a Genie garage door opener.I found the hack on Youtube and it works well.

bought for husband for electronic projects. works fine. save time for him, no need to assemble discrete parts together.

I've used two so far as the pulse signal for stepper motor drivers. They've worked fine for the short duration I've used them.

Wish it had better instructions but I was able to figure it out after a bit. worked fine though.

A handy circuit but lacking documentation. That said, it's easy enough to reverse engineer, but one shouldn't have to for a commercial device.