It occurred to me that if I had a say, 50% duty cycle PWM signal on a PWM pin, I should be able to see it.
Also, if it were controlled by a potentiometer, I should be able to see it change .
Yes ?
Yes.
Strange question. Why have you not just tried it?
It occurred to me that if I had a say, 50% duty cycle PWM signal on a PWM pin, I should be able to see it.
Also, if it were controlled by a potentiometer, I should be able to see it change .
Of course you can see it.
Controlled by a potentiometer how (exactly). (this is the forum. anything is possible)
Depending on the scope, it will even show you the frequency and duty cycle of said PWM signal in clear numbers.
PerryBebbington:
Yes.Strange question. Why have you not just tried it?
Perry, I don't know. Probably because I didn't really understand them.
hextejas:
I didn't really understand them.
Sounds like a good time to learn then 
Even my cheap 'scope has an "auto" button which will examine the input and figure out a decent way to scale and display it. And then you have a starting point to learn: change the time and voltage scales, see what happens. That cheap 'scope of mine has a pretty decent manual.
I found this on the forum: it shows a 50% duty (analogWrite of 128) on pwm pins of different frequencies.
This looks like it might help you understand?
vilmabergmann:
Sounds like a good time to learn thenEven my cheap 'scope has an "auto" button which will examine the input and figure out a decent way to scale and display it. And then you have a starting point to learn: change the time and voltage scales, see what happens. That cheap 'scope of mine has a pretty decent manual.
I found this on the forum: it shows a 50% duty (analogWrite of 128) on pwm pins of different frequencies.
That's pretty sexy vilma. What scope is it ?
hextejas:
Perry, I don't know. Probably because I didn't really understand them.
Fair point!
If you are serious about this as a hobby get an oscilloscope, has to be one of the most useful and flexible tools you can own.
hextejas,
PWM is continuous and repetitive so it shows-up nicely on an oscilloscope. Sine waves, square waves, clocks, etc., show-up nicely.
Most digital signals (data lines, address lines, serial data, etc.) look "messy" because they are not repetitive but it still can be useful to see if a digital line is stuck-high or stuck-low, or if it's shorted to another digital line it might sometimes be half-way between a zero and one. And, you can see the voltage levels.
I troubleshoot boards at work and if the board appears to be doing nothing I'll check a data line to see if there is any activity. (These boards have separate FLASH and RAM chips so it's easy to 'scope the address & data lines If there's no activity I'll check the CPU clock. Then if that's good I'll check all of the address & data lines to make sure they all have activity and to look for "weird" voltages/signals.
For the same reason, audio signals (real audio, not tones) looks messy, but it can still be fun to look at! (And sometimes you can get useful information from an analog signal.)
...I've been an electronics hobbyist for many years and I don't have a 'scope at home. Once or twice I've brought a hobby project into work to use the 'scope. If I was going to buy one, I'd speed a few-hundred dollars to get a decent one.
When i was at Tesla Deer Creek, Palo Alto, CA I had to design a signal conditioning circuit for a project (convert a -24V dc proximity sensor signal to a 5V TTL signal) and I couln't work on it at work because there was too much activity in the Engineering Lab and I couldn't concentrate so I bought a surplus 30Mhz scope for $95. I wasn't working with any fast signals (it was all analog) so it worked just fine. I was able to complete the design and my boss signed off on it the next day and since then I have used it many times
for PWM generator circuits and a switching power supplies this Nerdkits HV EL Backlight P.S.. It would have been hard to work on that without a scope.
It was totally worth it. I still have it and use it once in a while. I've had it 10 years now and haven't run
across a project that required anything more sophisticated even though I could totally afford a new scope
right now. I've used it to take scope screenshots for many posts. LarryD (I think) kept telling me to remove
the red $95 sticker on the front that was always visible in the screenshots. He thought it looked 'tacky' but
I liked it because it shows you can do something with nothing.
hextejas:
What scope is it ?
No idea, but I think just about any modern scope has a screen capture facility.
You can ask the person who posted it (JimboZA) from this post (4 1/2 years ago) . There's probably better deals now.
(Reply#5)