Nice. When I started , I thought a probe was just a piece of wire. When I heard of an x10, I started to realize it was not going to be that simple. I'm just starting to understand impedence and can appreciate that it is integral to signal qualitry. This video has helped in both the appreciation and why it is not just a simple piece of wire. Thanks IMSAI Guy. I'm looking forward to the remaining two videos in this exploration.
Only thing missing was when you were talking about the ground on the probe in the same breath as multimeters it's really important to mention that scope ground is connected to the earth pin (eventually, and unless you get fancy probes or scopes) so you can't just hook it on anywhere to get a differential reading like you can with a multimeter. Doing that lets the smoke out of something, if you're lucky it'll be the device, if you're not it's your scope. Learnt that one the hard way.
Thanks for the info! I'm checking out EEVBlog and you on scope probes as I got myself a Tek 468 and need something better. Always nice to learn new things.
May I make one suggestion that you might want to mention. When using a scope or any piece of test equipment with older vintage electronics that may not use a power transformer, such equipment is said to have a hot chassis. This is especially true if you’re working on an older a.m. table radios. Many years ago at the beginning of my career I did some serious damage to a rather expensive scope because I didn’t know this. From that day on anything that I am measuring with a scope or any other piece of test equipment is always connected to an isolation transformer
True. If you ground your scope-probe to the chassis, and plug in the 2 prong plug 1 way you get a ground loop. If you plug-in the AC 2 prong 180's out then the probes' ground wire vaporizes! (...and/or you get shocked! )
@@joeteejoetee In countries that use a three-wire electrical network connection, the GND of the probe is always connected to the ground of the electrical circuit, i.e. the PE terminal. For such measurements in these countries it is necessary to use an isolation transformer or a differential probe, these two requirements can be avoided by using an oscilloscope that allows battery power. However, it is necessary to realize that even the battery oscilloscope has BNC outputs GND for individual channels connected to each other, so again be careful where we connect them in the measured device. Have a nice day 🙂 Tom
@@Edisson. That's cool for you once you got modern 3-connector plugs/sockets. But like wise before the USA also had 3 wire plugs. Electronics in the USA in the 1940's+ had a non-polarized symmetrical plug and 50% of the time a "common/grounded" chassis, and 50% of the time a "HOT" chassis. I learned this in the 1960's (and my pre-teens) when I attempted to ground my radio chassis of an old SW radio to a water pipe in my bathroom, and the radio was too far away to reach, so holding ny radio chassis, I reached out and grabbed the base of the sinks' water-pipe, and I got the shock of my life! #NeverAgain !
@@joeteejoetee I know how it was done, I'm not the youngest, even in our country (at that time in Czechoslovakia) there were only two wires and 120V sockets, and the plugs were not flat, but round with the same length and diameter - thus luxuriously reversible. When switching to 220V (today 230), a PE contact was added to the sockets (the so-called EURO standard), until then it was fine, but one type of three-way socket was produced, where on one side the phase was transferred to the zero socket and this would devices sometimes carnage. And another funny thing is that all countries using the EURO socket standard have the phase on the right side when looking at the socket, the person who translated the standard into Czech at the time probably didn't know English very well and so as the only country that uses this standard has the phase on the left . It wouldn't hurt anything, but if a device has a "Flexo" type supply cable (factory-fused connecting plug) made in CZ, the phase is on a brown or black wire - these colors are in CZ for the phase wire when this cable is manufactured anywhere else in the world there will be a phase on the blue neutral wire - many times I've met people who don't know this and then are terribly surprised when they start to light up like a light bulb.
@@Edisson. what if you have a digital scope which has a switching power supply. The ground 3 wire plug was so annoying for me because I needed to connect my scop's negative to ground. I removed ground wires for my bench power supply (the clip) and my scope. Then I learned there were some annoying x y caps to scope's mains and ground inside it's power supply and they would interfere with high frequency signals. Then I had to spend $$ for an isolating transfer.
I got a cheap Chineseium probe with a cheap Chinese scope, the ground wire was'nt connected to the BNC plug. LOL. (I cut the lead near the plug and the ground was conected to the probe, just not the plug.) Great tutorial.
I almost exclusively use x10-only probes, can't think of the last time I needed to switch to x1 probe. If you care about noise in low level measurements there are better alternatives to switchable probes. Maybe a future video idea.... ;)
Very interesting and informative information. After buying a rigol 5000 series (not without your help :)), I thought about measuring high voltages. And I realized that for this it is necessary to have not only a 100x probe and an isolation transformer. But a differential probe may also come in handy. And this is not only a question of safety, but also a question of reliable information obtained by measuring signals not tied to the ground or the negative contact of the circuit. There is very little information on the net about this issue. I'd love to hear your recommendations.
Several folks have noted that you must be careful when placing the ground lead with vintage electronics. Very true, but there are other cautions about probe ground lead placement, too. In one of the early National Semiconductor videos an engineer (and no, it wasn't Bob Pease) cut the grounding terminal and temporarily suspended their oscilloscope with nylon rope above the bench to avoid any grounding issues. Now THAT is a floating ground. And also just a bit crazy. I'm sure we'll learn all about where to attach your probe's ground lead in Part 4, Probing Techniques. (grin)
It doesn't even have to be a vintage device, just a small oversight on the current switched-mode power source, as my colleague managed to do - I saw live what it means when it is said that the devil flew out of the box - the devil was a colleague accompanied by hellish lightning and smoke 😂
@@IMSAIGuyThanks. Teaching moment here..... the input is labeled 1 megohm 20pF. The P6075 says 10 megohm 12.5pF. In the video you told us to get a probe to match the scopes input? Clearly the numbers don't match. Is there some type of adjustment necessary for a 1x or 10x probe? Thanks....and I watch all your videos. This series is a great idea as it's very confusing to a beginner like me.
@@robbo6460 there is a range of adjustment (the one I show) that allows it to match. It is not clear what the range is on most probes. If you get a nice looking square wave when you adjust it on the calibrator output, that is all you need.
@@IMSAIGuyThanks. That makes total sense. Is there any drawback to using a 100mhz probe on a 200mhz scope? I have a generic 100mhz probe that squares up on the calibrator nicely. Do I lose bandwidth this way?
Hi, nice video, it's a shame that you didn't mention the galvanic connection of the GND probe and the PE terminal of the oscilloscope as Bob wrote here, and in that connection also the differential probe for direct measurement without the need to use an isolation transformer. One might also be interested to know that the probe cable is not ordinary coax, but a precisely manufactured cable with specific capacitance, inductance and resistance for the specific probe. I'm already looking forward to the continuation, have a nice day 🙂 Tom
Nice. When I started , I thought a probe was just a piece of wire. When I heard of an x10, I started to realize it was not going to be that simple. I'm just starting to understand impedence and can appreciate that it is integral to signal qualitry. This video has helped in both the appreciation and why it is not just a simple piece of wire. Thanks IMSAI Guy. I'm looking forward to the remaining two videos in this exploration.
Only thing missing was when you were talking about the ground on the probe in the same breath as multimeters it's really important to mention that scope ground is connected to the earth pin (eventually, and unless you get fancy probes or scopes) so you can't just hook it on anywhere to get a differential reading like you can with a multimeter.
Doing that lets the smoke out of something, if you're lucky it'll be the device, if you're not it's your scope. Learnt that one the hard way.
Ha ha, Yes, I've done that. (quite a bang and bye bye scope).
That's why I have a cheap Chinese rechargable one as well as my CRT Hitachi
Thanks for the info! I'm checking out EEVBlog and you on scope probes as I got myself a Tek 468 and need something better. Always nice to learn new things.
Graduated EE almost 4 years ago, still owning a oscilloscope have always been a dream.
Hope these basics come in handy when i own a oscilloscope.
Great refresher course. Thanks.
Very nice basics video. I like watching these
More to come!
May I make one suggestion that you might want to mention. When using a scope or any piece of test equipment with older vintage electronics that may not use a power transformer, such equipment is said to have a hot chassis. This is especially true if you’re working on an older a.m. table radios. Many years ago at the beginning of my career I did some serious damage to a rather expensive scope because I didn’t know this. From that day on anything that I am measuring with a scope or any other piece of test equipment is always connected to an isolation transformer
True. If you ground your scope-probe to the chassis, and plug in the 2 prong plug 1 way you get a ground loop. If you plug-in the AC 2 prong 180's out then the probes' ground wire vaporizes!
(...and/or you get shocked! )
@@joeteejoetee In countries that use a three-wire electrical network connection, the GND of the probe is always connected to the ground of the electrical circuit, i.e. the PE terminal. For such measurements in these countries it is necessary to use an isolation transformer or a differential probe, these two requirements can be avoided by using an oscilloscope that allows battery power. However, it is necessary to realize that even the battery oscilloscope has BNC outputs GND for individual channels connected to each other, so again be careful where we connect them in the measured device.
Have a nice day 🙂 Tom
@@Edisson. That's cool for you once you got modern 3-connector plugs/sockets.
But like wise before the USA also had 3 wire plugs.
Electronics in the USA in the 1940's+ had a non-polarized symmetrical plug and 50% of the time a "common/grounded" chassis, and 50% of the time a "HOT" chassis. I learned this in the 1960's (and my pre-teens) when I attempted to ground my radio chassis of an old SW radio to a water pipe in my bathroom, and the radio was too far away to reach, so holding ny radio chassis, I reached out and grabbed the base of the sinks' water-pipe, and I got the shock of my life!
#NeverAgain !
@@joeteejoetee I know how it was done, I'm not the youngest, even in our country (at that time in Czechoslovakia) there were only two wires and 120V sockets, and the plugs were not flat, but round with the same length and diameter - thus luxuriously reversible. When switching to 220V (today 230), a PE contact was added to the sockets (the so-called EURO standard), until then it was fine, but one type of three-way socket was produced, where on one side the phase was transferred to the zero socket and this would devices sometimes carnage. And another funny thing is that all countries using the EURO socket standard have the phase on the right side when looking at the socket, the person who translated the standard into Czech at the time probably didn't know English very well and so as the only country that uses this standard has the phase on the left . It wouldn't hurt anything, but if a device has a "Flexo" type supply cable (factory-fused connecting plug) made in CZ, the phase is on a brown or black wire - these colors are in CZ for the phase wire when this cable is manufactured anywhere else in the world there will be a phase on the blue neutral wire - many times I've met people who don't know this and then are terribly surprised when they start to light up like a light bulb.
@@Edisson. what if you have a digital scope which has a switching power supply. The ground 3 wire plug was so annoying for me because I needed to connect my scop's negative to ground. I removed ground wires for my bench power supply (the clip) and my scope. Then I learned there were some annoying x y caps to scope's mains and ground inside it's power supply and they would interfere with high frequency signals. Then I had to spend $$ for an isolating transfer.
I call the part that goes over the tip "a scope condom".
I got a cheap Chineseium probe with a cheap Chinese scope, the ground wire was'nt connected to the BNC plug. LOL. (I cut the lead near the plug and the ground was conected to the probe, just not the plug.) Great tutorial.
I almost exclusively use x10-only probes, can't think of the last time I needed to switch to x1 probe. If you care about noise in low level measurements there are better alternatives to switchable probes. Maybe a future video idea.... ;)
Very interesting and informative information. After buying a rigol 5000 series (not without your help :)), I thought about measuring high voltages. And I realized that for this it is necessary to have not only a 100x probe and an isolation transformer. But a differential probe may also come in handy. And this is not only a question of safety, but also a question of reliable information obtained by measuring signals not tied to the ground or the negative contact of the circuit. There is very little information on the net about this issue. I'd love to hear your recommendations.
I use my battery oscilloscope. makes it easy. th-cam.com/video/EUr3k9Jdx58/w-d-xo.html
Several folks have noted that you must be careful when placing the ground lead with vintage electronics. Very true, but there are other cautions about probe ground lead placement, too. In one of the early National Semiconductor videos an engineer (and no, it wasn't Bob Pease) cut the grounding terminal and temporarily suspended their oscilloscope with nylon rope above the bench to avoid any grounding issues. Now THAT is a floating ground. And also just a bit crazy.
I'm sure we'll learn all about where to attach your probe's ground lead in Part 4, Probing Techniques. (grin)
It doesn't even have to be a vintage device, just a small oversight on the current switched-mode power source, as my colleague managed to do - I saw live what it means when it is said that the devil flew out of the box - the devil was a colleague accompanied by hellish lightning and smoke 😂
I have a Tektronix 475 scope with 1M ohm 20pF inputs. What probe is recommended for this? Preferably a Tektronix probe. Thanks.
P6075 Probes came with the 475
@@IMSAIGuyThanks. Teaching moment here..... the input is labeled 1 megohm 20pF. The P6075 says 10 megohm 12.5pF. In the video you told us to get a probe to match the scopes input? Clearly the numbers don't match. Is there some type of adjustment necessary for a 1x or 10x probe? Thanks....and I watch all your videos. This series is a great idea as it's very confusing to a beginner like me.
@@robbo6460 there is a range of adjustment (the one I show) that allows it to match. It is not clear what the range is on most probes. If you get a nice looking square wave when you adjust it on the calibrator output, that is all you need.
@@IMSAIGuyThanks. That makes total sense. Is there any drawback to using a 100mhz probe on a 200mhz scope? I have a generic 100mhz probe that squares up on the calibrator nicely. Do I lose bandwidth this way?
@@robbo6460 yes it will limit you to 100
Hi, nice video, it's a shame that you didn't mention the galvanic connection of the GND probe and the PE terminal of the oscilloscope as Bob wrote here, and in that connection also the differential probe for direct measurement without the need to use an isolation transformer. One might also be interested to know that the probe cable is not ordinary coax, but a precisely manufactured cable with specific capacitance, inductance and resistance for the specific probe.
I'm already looking forward to the continuation, have a nice day 🙂 Tom
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