Variable Duty Cycle 1Hz-150KHz PWM Module from ICStation.com 

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Gadget Reboot will do!

I can’t remember the full specifications but there may be a little less output than input voltage because it’s being switched by a transistor that will have some loss across it but if it’s only 1.5 V no matter what, then it sounds like something strange is happening.

if it’s a respectable signal generator and not some $20 kit, it should be able to vary the duty cycle and frequency on at least the square wave output as well as adjusting the voltage and offset so it doesn’t necessarily just go from zero to some positive voltage so generally yes, and even better if it has a USB interface where you can set it up for automatic triggering and testing. I usually use the one in this video ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-pOSEm8VeXAU.html

@@GadgetReboot Thanks for the info!

What would be the intended behaviour of the system, does the first one basically enable the second one so when the first one is high, the second one generates its clocks and when the first one is low the second one stays disabled or something? The only way I can think of to control them is either using the Uart to send commands, or have two of them free running and then some other little digital logic circuit to gate them and enable them as needed.

@@GadgetReboot , I will try to explain better.I have two of these modules available.I have programmed the first one, in 'PULSE' mode, so as to give me an 'ON' time of half a second,and an 'OFF' time of half a second. I connected this module to the 'STOP' input port, that is behind the pcb of the second module. This last module, I programmed it,in 'PWM' mode, at a frequency of 100 Hz, 50% duty cycle , and I connected a small speaker to it;to have an auditory test of the correct functioning. The results?. Everything works except for the pulse times of the first module. By ear, the times are doubled. From half a second, I got a full second,as timing. Please give me the solution to this riddle.Thanks.

@@Jeanpaul465 that sounds like a different module than I have so I looked at IC Station and it sounds like this module ZK-PP1K so looking at the way they wired up the enable on the back it looks like it’s either left open or connected to ground so I wonder if one problem is it does not want to be directly driven high by the pulse generator, so I wonder how it would work if you connected the pulse to a transistor, so if you put the pulse on the base of an NPN through a 1K resistor or something, emitter to ground, collector to the appropriate enable pin on the second unit, then it will either be floating or connected to ground like they show with the push button. Otherwise how does it look if you separate the two units, if you manually ground the enable can you make the PWM start and stop as expected? And if you put a scope or a multi meter on the pulse output, does it look like it goes high and low at the right timing? Another reason to use the transistor to just connect the enable to ground but not any logic high, I wonder if that enable input is only 3.3 V tolerant because on my unit the UART is only 3.3 V so if I am powering the entire thing from 5 V I need a level translator to talk to those types of ports.

The output swings between the + and GND supply

Taco Bell would have the adverse impact of shortening the lifespan though. I like this little PWM generator and I think I want to get some similar little tools like that soon.