Oscilloscope

[Wade]

Does anyone have any good links or videos about how to use oscilloscope’s. They seem pretty complicated and I’d like to dig in and learn more about them.

[Gatecrasher]

I need to watch this myself.

https://www.eevblog.com/forum/beginners ... ss-(long)/

[Wade]

I need to watch this myself.

https://www.eevblog.com/forum/beginners ... ss-(long)/

Thank you

[pman92]

I would recommend getting a PC based scope.

You can get a brand new picoscope 2204a for a couple of hundred bucks if you're on a budget. It's not an automotive grade scope (eg input protection) and is the very base model pico, but it's still going to be very useful if you know what to do with it.

Automotive picos come up second hand from time to time if you keep your eye out. I've bought 2 of them.

In my experience nothing has come close to a picoscope in terms of capability and ease of use, especially in an automotive environment.

Every scope I've ever used that has been part of or bundled with a scan tool has been trash

[Wade]

I would recommend getting a PC based scope.

You can get a brand new picoscope 2204a for a couple of hundred bucks if you're on a budget. It's not an automotive grade scope (eg input protection) and is the very base model pico, but it's still going to be very useful if you know what to do with it.

Automotive picos come up second hand from time to time if you keep your eye out. I've bought 2 of them.

In my experience nothing has come close to a picoscope in terms of capability and ease of use, especially in an automotive environment.

Every scope I've ever used that has been part of or bundled with a scan tool has been trash

I picked up an Allosun 115a pretty cheap. But struggling to wrap my head around using it. I’ve also ordered a cheaper scope in the hopes that the simplicity of it may help with learning.

[antus]

What are you trying to do with it? Just get started or some task in particular? Generally speaking you want to set DC mode for voltages that are always + or - and AC mode for voltages that swing past the 0v and back (like a reluctor). Then set the voltage range per division so the height scale looks good (eg if you expect a 0-5v signal, you might be 1v/div so that scale fits on 5 on screen divisions, or 5v/div for one of them. Then you set time more or less until the wave looks about right for its frequency. Then there is a trigger, this moves up and down the side of the screen, and it is the voltage the scope will trigger on (when running in that mode). So for the 5v signal you might set trigger to 2.5v or so. This is high enough that it doesnt get triggered by noise and low enough that it reliably triggers. Then signals at pretty much any frequency are too fast to see as they happen, so the trigger happens consistently at the same place in a continuous signal, so the signal draws over its self continuously which means it looks still so you can get a chance to fine tune voltage or speed and see what you're dealing with. If your voltages are too high some problems have a 1x / 10x switch which will put resistance in the circuit to make the scope see 10x less voltage, which in practice means you can probe 10x more than you would be able to other wise. Then some scopes have features like auto that will take one scan from trigger to edge of screen and stop. Good for momentary signals you'll never catch manually. Sometimes you have 2 probes and you can get the trigger on the second one, so you might want to capture EST the moment Bypass comes on. Can do that. More of an electronic repair feature than needed for a car but its there. You'll find signals look very different on a scope compared to a logic analyzer. Logic analysers only show the high or low and show perfect digital waves. With a scope you can see all the noise and nastyness in an electrical environment. Voltages overshoot for a moment, edges that are not flat and so on. Its fascinating to see what's really on the wire. I know you were looking for a video, but if you're really trying to get started I hope that helps put your head in the right place or give you enough to start to probe a signal. If you have a low voltage AC power supply hook up to that and have a play until you can clearly see the 50hz sine wave (or whatever mess comes out of it, if its a cheap one).

[Wade]

What are you trying to do with it? Just get started or some task in particular? Generally speaking you want to set DC mode for voltages that are always + or - and AC mode for voltages that swing past the 0v and back (like a reluctor). Then set the voltage range per division so the height scale looks good (eg if you expect a 0-5v signal, you might be 1v/div so that scale fits on 5 on screen divisions, or 5v/div for one of them. Then you set time more or less until the wave looks about right for its frequency. Then there is a trigger, this moves up and down the side of the screen, and it is the voltage the scope will trigger on (when running in that mode). So for the 5v signal you might set trigger to 2.5v or so. This is high enough that it doesnt get triggered by noise and low enough that it reliably triggers. Then signals at pretty much any frequency are too fast to see as they happen, so the trigger happens consistently at the same place in a continuous signal, so the signal draws over its self continuously which means it looks still so you can get a chance to fine tune voltage or speed and see what you're dealing with. If your voltages are too high some problems have a 1x / 10x switch which will put resistance in the circuit to make the scope see 10x less voltage, which in practice means you can probe 10x more than you would be able to other wise. Then some scopes have features like auto that will take one scan from trigger to edge of screen and stop. Good for momentary signals you'll never catch manually. Sometimes you have 2 probes and you can get the trigger on the second one, so you might want to capture EST the moment Bypass comes on. Can do that. More of an electronic repair feature than needed for a car but its there. You'll find signals look very different on a scope compared to a logic analyzer. Logic analysers only show the high or low and show perfect digital waves. With a scope you can see all the noise and nastyness in an electrical environment. Voltages overshoot for a moment, edges that are not flat and so on. Its fascinating to see what's really on the wire. I know you were looking for a video, but if you're really trying to get started I hope that helps put your head in the right place or give you enough to start to probe a signal. If you have a low voltage AC power supply hook up to that and have a play until you can clearly see the 50hz sine wave (or whatever mess comes out of it, if its a cheap one).

First thing I’d like to do is mess around with setting amp gains in the car. But I’m sure it’ll come in handy when playing around with Arduino’s as well

[antus]

I'd be interested to know what you can come up with for that. Some scopes will have peak to peak volts so you can do that if you're looking for a voltage level. Or FFT if you need to 'see' the signal.

But you need to take in to account the response curve from your speakers. So you need a calibrated reference mike and tool to get that feedback, which you wouldn't use with a scope. In my car I used spectroid on my android phone (free app) that gives you an FFT with peaks from the phone mike, and then a track from spotify like "frequency sweep (20hz-20khz) by bunker analog, or there are plenty of others with similar keywords, and watch the sweep on spectroid and tweak the EQ on the head unit to flatten any peaks or troughs. Seems to work OK with just the phone and spotify.

https://open.spotify.com/track/13VYaewq4myWl4lavREvo7

Example of sectored. This is the second sweep, you can see the red line of peaks across the top and the current sweep on the 'waterfall' view at the bottom when I ran it a second time. This is just my computer speakers, but the illustration stands. It may not be studio gear but you can make quite a difference with little in the way of hardware.

[Wade]

I downloaded an app on my phone. Frequency generator. Allows you to set what hz you want. And been using other free software for designing speaker boxes ect. Allows you to make changes and get an idea of things.

[Wade]

There’s plenty of videos on yt on setting amp gains and cross overs ect. Using a dmm isn’t the most accurate way apparently. But works ok. https://youtu.be/fx2INydXxnQ?si=O-SHv6ghFpL9Bmkd