real word reasons to use an oscilloscope as a real tool? - Page 1
Forum section: electronics / beginners

author: cobbler
author_rank: Unknown
timestamp: November 17, 2015, 05:31:48 am
content: Been trying to wrap my head around oscilloscopes- it is finally starting to make sense thank God. The main thing that was hard to understand isWHENto use an oscilloscope!At first I thought it was just good to have because they look cool and girls go crazy over guys with them!Please correct me where I am wrong.Oscilloscopes simply help us LOOK at a signal. No matter fancy they are, no matter how many buttons and functions, the basic principle is always the same- we are looking at a signal and its ADVANCED characteristics/attributes.But why would we watch signals when we can watch TV instead?For most electronic enthusiasts using modern components, doing everyday troubleshooting/repair 99% of the time an oscilloscope is NOT going to help as much as common sense and a multimeter.Oscilloscopes are extremely valuable for SERIOUS circuit designers to make sure their design is working exactly as expected. In other words, doing QA, testing, and troubleshooting.When a SERIOUS designer is making sure their work is professional, they often have to have multiple scopes sensing different part of the circuit simultaneously to visually see that everything is "working as designed". The more complex the systems get... the chance for errors is higher... thus the need for doing extensive testing with scopes.A beginner should learn to use a scope on simple systems just to see how waveforms look. By starting to learn how to use the scope dials and triggers to quickly "lock on" the signal, we get better at using the scope and discovering how they can help us as we learn.The more often beginners look at the scope waveforms and their characteristics... the more we start to understand signals, because many people are visual.Professionals/advanced people who are more mathematically inclined can use the math functions of a scope to do all kinds of advanced tests and comparisons.Modern scopes with storage capability can be very useful for finding random glitches by sensing a signal for a long time and looking for random glitches in the signal by parsing the stored data.-For digital data being transmitted, looking carefully at the bytes, ACKS, etc help ensure signal /packet integrity.For snooping/groping/reverse engineering a digital signal, rough packet capture can done with modern scopes, although there are sometimes better tools for this like dedicated packet sniffers.Are there any other times when an oscilloscope should be used over any other tool?Enthusiasts working with older equipment can more often turn to an oscilloscope to get granular ability to find signal issues, this is useful when replacement parts are hard to get.Professionals repairing very high end equipment can do a very thorough test of every component in the system to make sure it is high quality workmanship.I know the value of being able to troubleshoot, I am a programmer.Troubleshooting is everything! If you can share specific circuit examplesof when using a scope is the best tool to troubleshoot it will greatly help beginners, it is hard to find practical tutorials/examples for beginners.Thx

author: ataradov
author_rank: Super Contributor
timestamp: November 17, 2015, 05:45:24 am
content: Quote from: cobbler on November 17, 2015, 05:31:48 amI'm quite literally laughing out loud. Never looked at the problem from this point of viewI've also never tried to watch a scope for entertainment value.

author: Psi
author_rank: Super Contributor
timestamp: November 17, 2015, 06:11:10 am
content: The vast majority of time i use my scope for MCU coding/debugging, to check all the i/o is doing what i coded.Sometimes i toggle an output at a specific point in the code to see when that's happening with reference to external signals

author: vk6zgo
author_rank: Super Contributor
timestamp: November 17, 2015, 06:20:54 am
content: "For most electronic enthusiasts, doing everyday troubleshooting/repair 99% of the time an oscilloscope is NOT going to help as much as common sense and a multimeter."Nope!!Many years ago,I was troubleshooting a piece of equipment----------looking at waveforms,then using a Multimeter to check the dc rails,etc.My Boss came past & said:-" You don't need to do that--------it's quicker to just leave the 'scope dc coupled & use it for everything!"I took that to heart.Fault finding a unit,I check the dc rails with the Oscilloscope,(in passing checking for hum or any other perturbation),then look at signal waveforms,check dc voltages on various devices,& so on.You don't need a voltage readout on the 'scope,just set the v/div to a convenient value,& count divisions.DMMs can be fooled:-CRT type TV sets commonly obtain voltages of around 160v for the vertical & audio output stages by an overwind on the Horizontal output transformer.This is rectified with a "fast recovery " diode,& filtered with a single electrolytic capacitor.On one occasion,my DMM read this supply as 120v dc,obviously a bit low,but not low enough to cause the collapsed vertical scans I was seeing.I borrowed an old BWD "CRO" from work,& the fault was obvious------a series of totally unfiltered half wave rectified half cycles.Obvious with an Oscilloscope,but not to the DMM!People fixing stuff & those designing stuff have quite different slants on 'scope usage.Designers like to be able to verify that the devicedoesproduce the voltage waveforms & levels they anticipated.

author: tautech
author_rank: Super Contributor
timestamp: November 17, 2015, 06:59:11 am
content: Quote from: vk6zgo on November 17, 2015, 06:20:54 amAll this ^^^^Ponder this:Many but not all would forgo all TE except for 1 piece....an oscilloscope, they are so versatile.

author: cyr
author_rank: Frequent Contributor
timestamp: November 17, 2015, 07:08:56 am
content: Quote from: cobbler on November 17, 2015, 05:31:48 am99% of the time I'd rather have a scope than a DMM if I had to choose. The scope pretty much "only" lets you look at signals, but what could possibly be more useful than that? It's not usually "advanced" characteristics you are after, but you can tell at a glance that "yep, voltage looks fine", "clock is there, seems OK", "reset pulse is long enough", "not too much ripple on the supply".

author: fubar.gr
author_rank: Unknown
timestamp: November 17, 2015, 09:39:22 am
content: In my opinion, not having a scope is a big stumbling block for a hobbyist.And there's no excuse today. Oscilloscope prices have dropped significantly. For the money you'd spend on a new smartphone (that will be obsolete within the next 3 years) you can get a kickass scope that will last you until the laws of physics do not apply anymore.And since the OP wants some real world examples:1) I recently got a DSO138 mini oscilloscope that won't show a signal. So I fed it with a known signal and tested whether any signal reaches the mcu's ADC. There was nothing, so there got to be something wrong in the analog front end. I finally found that one of the opamps in the quad opamp package was blown.2) Is my PWM signal driving the switching mosfet properly? Simply stick the scope probe between drain and source. If it is properly driven I should see a nice square wave with sharp edges. If it looks rounded or the voltage doesn't go to near zero when the mosfet is on, then something is wrong.

author: Shock
author_rank: Super Contributor
timestamp: November 17, 2015, 12:33:44 pm
content: Sounds like the OP was making a statement rather than asking a question.Multimeters when doing general repairs, troubleshooting, component checking, simple prototyping. As I mentioned a few days back most electronics troubleshooting is "go, no go".The advantages in a multimeter is it's quick and takes additional measurements, resistance, current, continuity, diode, more commonly now capacitance, temperature, frequency (along with voltage). Multimeters are not perfect for glitch capture, but many have min/max/avg and logging which can help.Oscilloscope fits in after that. Storage, Math, FFT and other DSO functions really expand on it. Then the logic analyzer when you need to see many signals at once and debug protocols. Spectrum analyzer to see the level or multiple different frequencies at once.Pointless jumping straight into an oscilloscope if you have not learned basic theory, not saying don't buy one, but this forum is full of people who are buying one, two, three oscilloscopes and can't use them because they don't have the fundamentals down yet. I'm sure the is a ton of buyers remorse, that is if they are not completely blinded by the fever associated with gear acquisition syndrome.That is why I think the best advice is for a beginner wait until you have some practical and theory skills down and see how you like the hobby then reward yourself first.Quote from: fubar.gr on November 17, 2015, 09:39:22 amIt will take a few years for the brain to catch up I think. Either that or for Dave to tell everyone they should look into a modern DSO, but that might cause general public panic and get him burned at the stake.

author: vk6zgo
author_rank: Super Contributor
timestamp: November 17, 2015, 02:25:37 pm
content: Imagine if you are presented with a microphone amplifier using the first schematic on this link page.http://circuitmodules.com/wp-content/uploads/2013/08/microphone-preamplifier-circuit-863x1024.pngThe customer says:- "I built it,& it doesn't work!"First situation-----No Oscilloscope:-You leap into action with your DMM.All the dc voltages look OK,so you are stuck with lifting component leads & checking them.Second situation-------You have an Oscilloscope:-Using the 'scope,you look at the base of Q1,while whistling in front of the mic.Nothing seen,so you look at the mic side of C2 & see audio.So C2 is faulty!You check closely,& discover one of the cap's leads is broken off internally.(this really happens!)There are alternatives:-This is a simple circuit,& you could find the faulty capacitor by disconnecting it (among others), & finding that it doesn't have the correct capacitance,or having the lead fall off.ORYou could inject tone from an audio generator in various places,but this would require another amplifier & speaker connected to the preamp output to make it audible.ORYou could use a "Signal Tracer" & probe various points as in the 'scope case.The first alternative is going to take considerably longer than using an Oscilloscope,& the other two require additional equipment.

author: AndyC_772
author_rank: Super Contributor
timestamp: November 17, 2015, 02:40:13 pm
content: Quote from: cobbler on November 17, 2015, 05:31:48 amIf you're trying to attract girls, I'm 99% sure an oscilloscope isn't going to help you. Try a motorcycle, or a little knowledge / interest in silver jewellery.QuoteTop tip: almost everything you read about what "serious" or "professional" engineers do, that isn'tactuallywritten by a professional engineer, is false - or at best, a vague generalisation that's dumbed-down to the point of uselessness.

author: Simon
author_rank: Unknown
timestamp: November 17, 2015, 06:16:27 pm
content: Is this guy for real ? he obviously has neber taken a TV apart from 30 years ago and found a diagram in it that showed oscilloscope waveforms to loof for on different points and even gave you a couple of alternative waveforms with a description of the problem they indicated. I could not live without a scope, it's like having eyes in your circuit.

author: Galaxyrise
author_rank: Frequent Contributor
timestamp: November 17, 2015, 07:05:32 pm
content: Quote from: cobbler on November 17, 2015, 05:31:48 amThis probably comes down to what you think "most electronic enthusiasts" are doing. Are they using PWM for anything (like controlling a servo)? Using a 555 timer? () Using opamps that might be unintentionally oscillating? Looking for power supply ripple?I'm definitely not more advanced than an "enthusiast" and I've encountered things that I could only measure/test with my scope. I'm also perfectly willing to believe there are enthusiasts that haven't had it come up yet. Enthusiast is a very broad term.

author: cobbler
author_rank: Unknown
timestamp: November 17, 2015, 08:14:36 pm
content: Thanks for all the replies. I am seriously trying to learn when is the best time to use an oscilloscope. I am not making a statement in the original post, I knew that it needed correction.I am at early stages of learning. I am a programmer by trade and have that part down well, now I want to focus on electronics and am just starting to get my feet wet.It is very hard to find any tutorials that show how to troubleshoot a circuit with an oscilloscope, so everybody's comments are extremely helpful.Especially all the real world examples you've shared. please keep suggestions flowing it is really helpful for beginners.Thank you!

author: KL27x
author_rank: Super Contributor
timestamp: November 17, 2015, 08:17:19 pm
content: DMM = average voltage, diode check, continuity test, ohm meter, current. Besides current (which is simply a function of voltage measurement on a shunt resistor, which a scope can also do),the only one of those features that works on a live circuit is the voltage test.And it only shows the average voltage. It doesn't give you the slightest indication if the voltage is steady or actually a signal/wave, or if there's any ripple/noise. A DMM can't even tell you where power is being switched completely on/off where the frequency exceeds 10ish Hz. And in the world of electronics that can be exceedingly slow. It not like you can always flip a switch, measure, flip off switch and measure. Some of these switches are being cycled thousands of times per second.This is where the oscilloscope comes into the picture. It logs voltage over time. A scope can "zoom" in/out by adjusting the timebase, to look at high speed oscillations or even be used as a logging voltmeter.It takes the one thing a DMM can do on a live circuit, and it takes it to another level of utility.A scope is a poor replacement for a DMM and vice versa. A scope is good for nothing on unpowered circuitry. A DMM is blind to high speed voltage changes.

author: Simon
author_rank: Unknown
timestamp: November 17, 2015, 09:11:58 pm
content: It's not a question you need to ask really. As soon as you have a problem or want to verify something you will be wishing you have a scope.People who come from programming to electronics often underestimate what goes on outside the chip and the analogue nature of even a digital circuit.For example, you can consider a digital signal and off/on, as a programmer it's all you need to know, but..... take a look at that "square wave" it could have ring, it has a rise and fall time, different cables will have different effects, put a fast square wave down a pair of distant conductors and look at wehat comes out of the other end, now twist those cables and see the difference.From a coding background you may have more appreciation for something like the scope i bought today, the Rigol DS1054Z (already "converted to DS1004Z) it can decode serial busses, even to a software engineer this is a useful tool.

author: xwarp
author_rank: Frequent Contributor
timestamp: November 17, 2015, 09:17:36 pm
content: Just like in auto mechanics, there is a tool for the job.A spark gap will show you there is a spark,But the spark gap tester won't tell you what the spark is doing under operating conditions, but a scope with a capacitive probe can.Another opinion, a multimeter provides a quantative measurement where you know what the values are supposed to be, whereas a scope provides a qualitative measurement, I.E. try looking at the R.F. modulation of the final outputs of a transceiver with a multimeter and see how much information you can derive from it to determine where a fault may be.My point, with experience and time, you will eventually be able to take a failing piece of equipment, and with it's known symptoms, be able to look at a schematic and determine which tools you will need to properly diagnose the failure.

author: cobbler
author_rank: Unknown
timestamp: November 17, 2015, 09:19:57 pm
content: Quote from: Simon onTodayat 03:11:58 AMThanks, it makes sense what you're saying. I've met programmers who were extremely book smart, but in the real world could not program there way out of a wet paper bag. As a programmer the best skill anybody can have (imo) is being an quick troubleshooter/debugger. That is why I am so eager to see real world examples. I ordered a scope on ebay Sunday and it is arriving today, can't wait to start learning how to put it to use.Where is the rep button? Do I need a certain number of posts to give rep? +rep for all those that have posted. Thx

author: DimitriP
author_rank: Super Contributor
timestamp: November 17, 2015, 09:36:57 pm
content: QuoteFortunately, (most of the time, except when not) this 'aint no stack exchange.

author: Simon
author_rank: Unknown
timestamp: November 18, 2015, 07:01:04 am
content: Quote from: cobbler on November 17, 2015, 09:19:57 pmI had a guy that needed to turn on a relay and check that a voltage came out of the switch and if not switch it off again. The relay would just click on and off. Luckily i was thinking out of the chip and figured that he was turning the realy on and immediately (1uS later) checking for a voltage and then 1uS later not finding anything turning it off again, the relay that needs some ms to operate did not even get a look in. Could have taken hours to diagnose without a good guess at how stupid the programmer (and circuit designer) had been. In this case no scope was needed.

author: mich41
author_rank: Regular Contributor
timestamp: November 18, 2015, 10:15:40 am
content: Quote from: Simon on November 18, 2015, 07:01:04 amOh, but it would be hugely useful if it was you who wrote this code believing that it's gonna work, trust me

author: madires
author_rank: Super Contributor
timestamp: November 18, 2015, 12:27:36 pm
content: Last week I had an issue with a bidirectional I/O level shifter (based on a MOSFET and two resistors) and the scope literally solved the problem. While probing both sides of the level shifter it suddenly started to work when one probe was connected to the high voltage side. When I removed the probe the level shifter stopped working. Connected the probe again and the level shifter was working. Hmm, probe/scope impedance? It can't be the resistance. So I grabbed a 12pF ceramic cap, whacked it into the breadboard and the level shifter was happy. Me too, and a little bit puzzled.

author: daqq
author_rank: Super Contributor
timestamp: November 18, 2015, 12:49:12 pm
content: QuoteTo be fair, you can watch TV on (some) scopes...QuotePWM measurement for whatever you are controlling (LEDs, motors, servos, heaters...), switched power supplies, various busses (I2C, SPI, USART...), noise on the power lines, amplification... basically measuring anything that changes over time, anything fast. I cannot imagine working without an oscilloscope.

author: Simon
author_rank: Unknown
timestamp: November 18, 2015, 12:50:43 pm
content: I made a level translator from 12 to 24V for a customer. Simple as it was I bloody well wanted to see the reults on my scope. I was for examle able to verify the maximum frequency i was happy for it to run at. And that could only be done by looking at the waveform coming out and deciding when I was no longer happy with the look of it.

author: tggzzz
author_rank: Super Contributor
timestamp: November 18, 2015, 01:40:00 pm
content: Quote from: AndyC_772 on November 17, 2015, 02:40:13 pmUnfortunately too many "professional" engineers also have severely blinkered experience, maybe 20 years experience consisting of 1 years experience repeated 20 times.These are relatively easy to spot. Look for condident assertions that don't have a clause indicating where the assertion is valid and/or invalid.Of course, non-professional engineers and other people also make similar "global" assertions.

author: tggzzz
author_rank: Super Contributor
timestamp: November 18, 2015, 01:42:44 pm
content: Quote from: DimitriP on November 17, 2015, 09:36:57 pmAmen to that. Unfortunately too many sites aim to emulate crock exhange's success.

author: tggzzz
author_rank: Super Contributor
timestamp: November 18, 2015, 01:44:57 pm
content: Quote from: madires on November 18, 2015, 12:27:36 pmAnd there's the source of your problem.Congratulations on battering this particular instance of your circuit into temporary submission.

author: madires
author_rank: Super Contributor
timestamp: November 18, 2015, 02:20:15 pm
content: Quote from: tggzzz on November 18, 2015, 01:44:57 pmOne of my first thoughts was that it's a breadboard problem. But I haven't seen any oscillation and the problem with breadboards is that they got too much capacitance between the contact strips. If you got a good explanation, I'd happy to hear it

author: smbaker
author_rank: Regular Contributor
timestamp: November 18, 2015, 04:14:57 pm
content: Quote from: cobbler on November 17, 2015, 09:19:57 pmAbout a decade ago, I put together a CNC sherline milling machine, and I implemented a joystick option so that I could manually operate the milling table at a specific speed. I used the joystick to control direction and a 555 timer to control speed. As I turned up the speed control, the milling table would start to move erratically. I double and triple-checked the 555 timer circuit to try to find my mistake.Finally, I got the scope (a B&K precision 20Mhz analog) out and probed the circuit in a few places. It became immediately obvious what was wrong -- I had selected too small a filter capacitor on my power supply. There was nothing wrong with the timer circuit itself, rather it was the power feeding the circuit that was the problem.These days I often reach for the scope instead of the mulitmeter, just because it provides more information.Scott

author: tggzzz
author_rank: Super Contributor
timestamp: November 18, 2015, 04:40:21 pm
content: Quote from: madires on November 18, 2015, 02:20:15 pmThat's only the least of it.Much more important in high speed circuits is too much inductance, and dynamically variable resistance.Work out the inductance of your wires (assume 1nH/mm) the change in current that flows during a transition, the transition time (signal repetition time is completely irrelevant), and plug the values into the elementary equation V= Ldi/dtWork out the inductance and capacitance, and calculate the resonant frequency.When you have correctly concluded that high speed circuits are unlikely to work reliably on breadboards, investigate the other techniques that work adequately.

author: Ampere
author_rank: Regular Contributor
timestamp: November 18, 2015, 10:57:07 pm
content: I'm working on an Arduino project which relies on two PWM signals. The duty cycle of both signals and ratio between the two duty cycles are controlled by their own respective potentiometer. I.e. The first pot adjusts the duty cycle of both from 25%/25% to 50%/50% and then the second pot changes the duty cycles from 50%/50% to 50%/75% or 25%/50%.I might be a beginner, but I would think that even a pro would test the circuit how I did. I connected a probe to each output and watched how the signals changed in response to the inputs. I guess I could have used my DMM to monitor the duty cycle, but then I would have needed another DMM and I probably wouldn't have noticed the bug that occurred when the duty cycle rolled over past 100%.

author: vk6zgo
author_rank: Super Contributor
timestamp: November 19, 2015, 12:26:01 am
content: People will sometimes go to extreme lengths to avoid using an Oscilloscope.At one employer,we made vehicle simulators.The simulator's display had a "Test" function where you could check all the control settings & adjust them during initial set up.Several of these controls output a PWM signal which was integrated passively,fed to a couple of Op Amps followed by an ADC*which was part of a "Mainboard" which interfaced with a PC.The Op Amp circuit had adjustments of voltage range & offset,which had to be" tweaked" to both "centre" their output on,& make best use of, the ADCs range of acceptable inputs.The standard way of setting these up was to look at the "Test" display on the PC screen .This involved "dancing" the adjustments in & out till they were centred on,& just filled the display window.(which was a bit like the "pretend" analog scale on a DMM.)I said:-"Why not set one unit up in the "classic" way,then look at the signal into the ADC with an Oscilloscope,keep a record of the voltages,& preset all the others using a 'scope?"They wouldn't even consider it,& continued wasting hours doing it the hard way!*No,I don't know why they didn't just sample the PWM directly---I just worked there!

author: dolphin42
author_rank: Newbie
timestamp: November 19, 2015, 01:15:47 am
content: What have I used a scope for, engineering-wise?* Ensuring that pulses have a fast enough transition in a remote sensing application, where a semi-passive input circuit supplies a small current over a lopng line in the presence of line voltage.* Making sure that output stages are being driven properly. (solenoid drivers, switching supplies, audio amplifiers, motor drivers, etc etc)* Watching communication busses for slew rate and glitches (and with the new capabilities of even simple digital scopes, doing simple protocol debugging - of course the new scopes can do a lot of heavy lifting there that used to take building circuits to decode the buss to watch it work)* Checking that LCD drive signals really are always exactly 50% in simple arrangements, and with at least two traces, depending, checking the switching voltages on a muxed one.* Simple logic analysis of a digital circuit, is the clock alighed properly with the signal to be clocked in? Does the PWM go all the way from off to on as you vary the range?* In any servo circuit (motor control, power supplies of the regulated persuasion, etc) is the contro,. of the circuit calm and controlled? Or is it unstable and oscillating around the center of the control voltage, and losing energy to switching losses that it needn't)* When any sort of inductive load, are the freewheeling clamps doing the job of keeping the output devices from blowing up? (A more general case I've already stated above indirectly)* Are unwanted signals in a circuit from adjacent signals? Parallel wires will tend to couple a signal in one wire onto other adjacent ones.* Is power supply instability causing the circuit to misbehave when loaded to its' maximum?* Where is signal loss happening in a chain of amplifier stages? (Less of a problem in the IC age, perhaps but still a valid problem)Anytime I develop a circuit, I just "have to" watch it work. If I can't see it working, even if it works right off the bat, I get a little twitchy about it.And once you have enough experience, to know what a circuit should be doing, the same thinking applies. And when you get a broken circuit that used to work, while static checking is often faster (e.g. are the caps open in a switcher, is often the best first test, with the circuit off) sometimes you gotta see it working in real time.(THis is my first post in this forum, but I can't resist chiming in LOL even if I'm mostly repating things others have said)

author: Smokey
author_rank: Super Contributor
timestamp: November 19, 2015, 01:41:25 am
content: Quote from: cobbler on November 17, 2015, 05:31:48 amNo, no no... It's not the scope.. The girls love the MULTIMETERS!

author: fivefish
author_rank: Frequent Contributor
timestamp: November 19, 2015, 02:38:51 am
content: Wait... a scope is a real tool for doing useful work?I thought the point of buying a scope is so that we can hack it and then find all the bugs and imperfections, weird behavior, freezing scenarios, obscure combinations and permutations of switches and settings that will cause it to crash so we can have something to talk about.

author: grifftech
author_rank: Frequent Contributor
timestamp: November 19, 2015, 03:51:28 am
content: Quote from: Simon on November 17, 2015, 06:16:27 pmI think that you mean never .

author: crispy_tofu
author_rank: Super Contributor
timestamp: November 19, 2015, 11:21:19 am
content: Quote from: Smokey on November 19, 2015, 01:41:25 amThose probes are in the wrong jacks...

author: HighVoltage
author_rank: Super Contributor
timestamp: November 19, 2015, 11:41:00 am
content: Quote from: AndyC_772 on November 17, 2015, 02:40:13 pmWell, I had one 23 year old German girl working in my lab and she loved the scopes as much as I do. Even asked if she could take one home to play with. May be there are more of them out there but I have only met one so far.This is a funny thread!

author: madires
author_rank: Super Contributor
timestamp: November 19, 2015, 01:43:06 pm
content: Quote from: tggzzz on November 18, 2015, 04:40:21 pmIt's around a few mV in my case. This shouldn't be the cause.Quote from: tggzzz on November 18, 2015, 04:40:21 pmI don't disagree, but 1MHz digital I/O isn't particularly high speed. A 74HC4050 used as unidirectional level shifter works fine with the same breadboard and same circuit. I've had circuits on the breadboard running around 10MHz without much issues. Though I wouldn't go much higherAnyway, identifying or specifying the maximums of a breadboard is a good application for a scope.

author: Smokey
author_rank: Super Contributor
timestamp: November 19, 2015, 06:27:30 pm
content: Quote from: crispy_tofu on November 19, 2015, 11:21:19 amThat's what she said?

author: tggzzz
author_rank: Super Contributor
timestamp: November 19, 2015, 07:02:09 pm
content: Quote from: madires on November 19, 2015, 01:43:06 pmShow your working, including length of wires, impedance (not resistance) of loads, type of driving logic, transition times.QuoteSince you quote "1MHz", you clearly don't understand the issues. The problems will manifest themselves at 100kHz. Or 1Hz. Or 0.1Hz. Let me put it more directly: what do you think is the highest frequency present in a 1MHz digital signal, or a 0.1Hz digital signal?Please check you answer by reading and understandinghttp://www.sigcon.com/Pubs/pubsKeyword.htm#rise%20time

author: madires
author_rank: Super Contributor
timestamp: November 19, 2015, 07:12:29 pm
content: Quote from: tggzzz on November 19, 2015, 07:02:09 pmI think you misunderstood me, I'm very well aware about rise times, pulses and Mr. Fourier.

author: crispy_tofu
author_rank: Super Contributor
timestamp: November 19, 2015, 08:32:19 pm
content: Quote from: Smokey on November 19, 2015, 06:27:30 pmRed is in the 10A jack, black is in the volts-ohms jack.What about the common?

author: smbaker
author_rank: Regular Contributor
timestamp: November 19, 2015, 10:16:09 pm
content: It's good you clarified, otherwise we could have misinterpreted and thought you had an unusually long thumb.

author: c4757p
author_rank: Super Contributor
timestamp: November 19, 2015, 10:33:51 pm
content: Subtle as always, timb

author: Simon
author_rank: Unknown
timestamp: November 20, 2015, 06:54:09 am
content: Quote from: Smokey on November 19, 2015, 01:41:25 amHave a look around ebay and look at how crazy the chinese ones go for power inverters, a 5KW one can get you up to 3 girls drooling over it at once.

author: timb
author_rank: Super Contributor
timestamp: November 20, 2015, 08:54:08 am
content: Quote from: smbaker on November 19, 2015, 10:16:09 pmI do. It's both! There was this industrial accident and... It's a *long* story. You know what else is long? My pen is. It's hard to write with sometimes. You know what else is hard? Diamonds.Sent from my Tablet