what an oscilloscope recommended for a woman passionate about electronics?

[borjam]

-ejeffrey: I see that you recommend more channels than band. I don't know if in my simple repairs is better 2 channel but 200mhz, or only 100mhz but 4 channel; I don't make circuits, I only repair faults. now I only use the multimeter, but I would love to find faults even using an oscilloscope.

I would consider the Rigol DS1000Z for four channels, Siglent 1202X-E for two.

So. Are you debugging digital stuff like SPI buses? If the answer is no, you don't need four channels.

I own both the Rigol and the Siglent and I think the Siglent is a better value for money unless you need four channels. Single price, no options, nothing to hack, 200 MHz, and it works pretty well.

For analog signals the Siglent 1202X-E has an important edge: the persistence modes are better implemented than on the Rigol DS1000Z. I have used mine, for example, to adjust the transmission envelope of a radio transceiver, one of the applications that some nostalgics think is better achieved with an analog scope.

I wouldn't get the cheaper Rigol DS1000E series, too old. Both Rigol and Siglent have made important improvements during the last two years.

A plus for Siglent (I also own one of their spectrum analyzers) they are learning to listen to their customers, something very unusual for Chinese companies. So they have been making important improvements in firmware updates.

I think these models (and unless you need four channels I insist, the sweet spot is the Siglent SDS1202X-E) offer a big value for money and they have capabilities you wouldn't have dreamed of a few years ago.

[Mr. Scram]

thanks tggzzz:
ok, the ground of the oscilloscope must not be removed.
I want to hope that the external frames of the oscilloscopes are not metallic...
I seem to understand that the main problem is to connect the probe ground in the wrong place.. but I see no danger to the user, only damage to the circuit or oscilloscope.
Yes, I meant between circuit tested and mains supply (isolation trasformer)
Then using probes Hv the dangers are minor (but only for health oscilloscope?)
Thanks for safety link ;-)
Charlotte

In most oscilloscopes ground is shared. This means that all BNC connectors or leads attached to these could have mains voltages on them. This obviously leads to potentially dangerous situations if measures to mitigate this danger are disabled.

[CharlotteSwiss]

-ejeffrey: I see that you recommend more channels than band. I don't know if in my simple repairs is better 2 channel but 200mhz, or only 100mhz but 4 channel; I don't make circuits, I only repair faults. now I only use the multimeter, but I would love to find faults even using an oscilloscope.

So. Are you debugging digital stuff like SPI buses? If the answer is no, you don't need four channels.

I think these models (and unless you need four channels I insist, the sweet spot is the Siglent SDS1202X-E) offer a big value for money and they have capabilities you wouldn't have dreamed of a few years ago.

thanks borjam 
Now I've never been interested of the SPI signal, but if I had the chance why not?
it's curious, you're one of the few who recommend fewer channels and more bandwidth
quiet my choice does not include ds1000e rigol
The models of choice should be: rigol ds1054z, rigol ds1202z-e, and the basic model Siglent.
From what I read here, it seems that Siglent is slightly superior to Rigol in terms of quality, but it costs more...
Charlotte

[tggzzz]

thanks tggzzz:
ok, the ground of the oscilloscope must not be removed.
I want to hope that the external frames of the oscilloscopes are not metallic...

Only on rare expensive scopes is that relevant.

I seem to understand that the main problem is to connect the probe ground in the wrong place.. but I see no danger to the user, only damage to the circuit or oscilloscope.

If correctly grounded and the probe shield is connected to an incorrect point, then the current will flow through the probe, lead, scope to ground - but not through the person.

How much current will flow depends on what you have connected it to. For example, even the mains neutral might be at a few volts relative to earth and has low impedance, so large currents might flow. That might cause fires, burns, sudden loud noises, and a startled person can hurt themselves.

Yes, I meant between circuit tested and mains supply (isolation trasformer)
Then using probes Hv the dangers are minor (but only for health oscilloscope?)
Thanks for safety link ;-)
Charlotte

Read the references and think about them!

[CharlotteSwiss]

In most oscilloscopes ground is shared. This means that all BNC connectors or leads attached to these could have mains voltages on them. This obviously leads to potentially dangerous situations if measures to mitigate this danger are disabled.

I did not understand the speech well 
is shared by whom?
in practice it is dangerous if the earth is disconnected from the 230vac oscilloscope cable?
yes this I understand, I will not commit this fool..
 

[CharlotteSwiss]

If correctly grounded and the probe shield is connected to an incorrect point, then the current will flow through the probe, lead, scope to ground - but not through the person.

How much current will flow depends on what you have connected it to. For example, even the mains neutral might be at a few volts relative to earth and has low impedance, so large currents might flow. That might cause fires, burns, sudden loud noises, and a startled person can hurt themselves.

this is comforting. However, I wouldn't touch parts of the circuit with my hands while taking the  oscilloscope measurements
Of course buying a new oscilloscope and detonating it wouldn't be a good thing..

-------------------------------------------

I have just read, for example, the safety instructions of the DS1054..
In substance, the danger could only be present if the probe ground is connected to a point of the circuit with high voltage..
Just make sure first with a multimeter that the point intended for the mass of the probe is not Hv .. and fear passes

I start to be more calm, maybe I can also use an oscilloscope without doing damage..
 

[magic]

This whole thread

There is a simple way to avoid shock hazard for a beginner:

Don't stick the probes (nor their grounding clips) into anything involving high voltage (mains sockets, power supplies, Tesla coils, ...).
If you probe in a device with a built-in mains power supply, locate the transformer which isolates mains from the low voltage stuff and only touch the low voltage stuff which you would normally touch while simply operating the device.
If there is no transformer and a lot of little bottles with metal in them, run

If you stick to this, you will be about as safe as when using any random electric appliance. Which is to say, they all are designed to make a dangerous failure almost impossible (until you get clever with modifying them).

When you actually have a need to fix a clearly failed power supply, then you may start to worry about safe probing in HV circuits.

[CharlotteSwiss]

This whole thread

There is a simple way to avoid shock hazard for a beginner:

Don't stick the probes (nor their grounding clips) into anything involving high voltage (mains sockets, power supplies, Tesla coils, ...).
If you probe in a device with a built-in mains power supply, locate the transformer which isolates mains from the low voltage stuff and only touch the low voltage stuff which you would normally touch while simply operating the device.
If there is no transformer and a lot of little bottles with metal in them, run

If you stick to this, you will be about as safe as when using any random electric appliance. Which is to say, they all are designed to make a dangerous failure almost impossible (until you get clever with modifying them).

When you actually have a need to fix a clearly failed power supply, then you may start to worry about safe probing in HV circuits.

magic...when you wrote, at the same time I added the last part above
I have just read, for example, the safety instructions of the DS1054.. ecc ecc..

 

[magic]

In substance, the danger could only be present if the probe ground is connected to a point of the circuit with high voltage..

Or if the tip of the probe ends up getting mains voltage on it. Most probes will take 230V AC perfectly happily but they may not survive transient overvoltages present on mains. The same CAT ratings that apply to DMMs also apply to probes. Most probes should be considered CAT I unless they are rated otherwise.

Just make sure first with a multimeter that the point intended for the mass of the probe is not Hv .. and fear passes

You should also be sure it isn't LV
The probes should only ever be grounded to the actual ground of the circuit. Connecting them to a 5V supply will not kill you but may release magic smoke somewhere.

Most of the time ground is easy to find by looking at connectors on the device.

[tggzzz]

This whole thread

There is a simple way to avoid shock hazard for a beginner:

Don't stick the probes (nor their grounding clips) into anything involving high voltage (mains sockets, power supplies, Tesla coils, ...).
If you probe in a device with a built-in mains power supply, locate the transformer which isolates mains from the low voltage stuff and only touch the low voltage stuff which you would normally touch while simply operating the device.
If there is no transformer and a lot of little bottles with metal in them, run

If you stick to this, you will be about as safe as when using any random electric appliance. Which is to say, they all are designed to make a dangerous failure almost impossible (until you get clever with modifying them).

When you actually have a need to fix a clearly failed power supply, then you may start to worry about safe probing in HV circuits.

It looks like you are unfamiliar with typical failure mechanisms. I suggest you learn from the "Repair" and "Test Equipment" subforums.

Frequently the failure is in the PSU: electrolytic capacitors are a traditional culprit for several different reasons (and the first thing you look at), some mains filter capacitors are known as "delayed action smoke generators" for good reasons, but diodes and transistors also give up the ghost.

Only if the PSU is working correctly do you bother to look at other parts of the circuit.

[CharlotteSwiss]

sorry, I didn't explain myself well.

safety precautions:
-the mass of the probe must be positioned only on the zero potential parts of the circuit to be analyzed
-the tip of a probe must be positioned only on the circuit parts, where the vpp is not higher than the probe limit
-to measure circuit parts with high voltage with the probe tip, it is necessary to purchase Hv probes

Note:
the mass of the probe is usually shared with the earth of the home electric system: therefore if I place the mass of the probe on a part of the circuit that is not potential-free, the life-saving differential will intervene .. but the flare or some damage could occur

-------

now I can make my choice:

-rigol ds1054z      4ch/50mhz(100hack)
-rigol ds1202z-e   2ch/200mhz
-siglent sds1102   2ch/100mhz
-siglent sds1202   2ch/200mhz

my resources allow me to choose only among these 4 models

before entering here in the forum I didn't understand anything about oscilloscope, now (after only 24 hours) I'm improving..

 
Charlotte

[tggzzz]

Just make sure first with a multimeter that the point intended for the mass of the probe is not Hv .. and fear passes

You should also be sure it isn't LV
The probes should only ever be grounded to the actual ground of the circuit. Connecting them to a 5V supply will not kill you but may release magic smoke somewhere.

The classic is connecting the probe shield to mains neutral. If the mains neutral is at mains earth potential there is no problem, but in many electric installations that is improbable. It may only be a few volts away from mains earth potential, high currents can flow.

Most of the time ground is easy to find by looking at connectors on the device.

But not always. I've debugged circuits where a TTL IC's Vcc is at -12V in one place and -17V in another.

[tggzzz]

sorry, I didn't explain myself well.

safety precautions:
-the mass of the probe must be positioned only on the zero potential parts of the circuit to be analyzed
-the tip of a probe must be positioned only on the circuit parts, where the vpp is not higher than the probe limit
-to measure circuit parts with high voltage with the probe tip, it is necessary to purchase Hv probes

Note:
the mass of the probe is usually shared with the earth of the home electric system: therefore if I place the mass of the probe on a part of the circuit that is not potential-free, the life-saving differential will intervene .. but the flare or some damage could occur

Basically yes.

The question is then determining which parts are at the same potential as the protective mains earth. If in doubt, a good technique is to use a voltmeter to measure the potential, but there can be a difficulty there.

Modern digital multimeters have a high input impedance, typically 10Mohm. There can be low levels of leakage in the PSU, e.g. due to capacitive coupling (possibly in real components e.g. in cheap nasty SMPSs, possibly parasitic capacitance). If you have a 0.1uA leakage, it might not affect the circuit, but would cause 1V to "appear" across the 10Mohm resistor. Old multimeters are better in that respect because they draw 50uA at full scale deflection, so small leakage currents won't look like a large voltage.

before entering here in the forum I didn't understand anything about oscilloscope, now (after only 24 hours) I'm improving..

We all start from nothing, we all learn, we all make mistakes - even experienced people. Yes, I have accidentally destroyed equipment in the past, through carelessness.

As my daughter was taught by her flying instructors, "have fun, safely"
As I taught her, "Let's make new mistakes"

[CharlotteSwiss]

exactly, the greatest difficulty lies in finding the point where to place the mass of the probe. But... looking at the scheme of the card if available,
 or a gnd screen printed on the card will be somewhere... 

There are also activities that do not allow error, it is not contemplated... I practice climbing in my spare time, a mistake could simply be fatal
But in my life I learned that when you know you can't go wrong, you will hardly be wrong
;-)

[magic]

It looks like you are unfamiliar with typical failure mechanisms.

You might be unfamiliar with the concept of "first measure the (secondary, low voltage, isolated) output of the PSU and only poke its internals if something is wrong and it doesn't look like it's the secondary capacitors". May I suggest lurking more?

[tggzzz]

There are also activities that do not allow error, it is not contemplated... I practice climbing in my spare time, a mistake could simply be fatal
But in my life I learned that when you know you can't go wrong, you will hardly be wrong
;-)

I backpacked around India with her when she was 14, flying gliders solo before she could drive, skiing, etc. Gave her confidence to tell me when she was an 18yo, "Dad, I've just bought a flight to Australia for a 6 months trip"

As you clearly know, some risks are worth taking once you understand and control them.

[rstofer]

now I can make my choice:

-rigol ds1054z      4ch/50mhz(100hack)
-rigol ds1202z-e   2ch/200mhz
-siglent sds1102   2ch/100mhz
-siglent sds1202   2ch/200mhz

my resources allow me to choose only among these 4 models

It would be ideal to put the local cost (including taxes) alongside the models.  For example, I wouldn't include the SDS1102 unless it was a LOT cheaper than the DS1054Z.  What's the point of 2 channels at 100 MHz unless it is a LOT cheaper than 4 channels at 100 MHz?  Then there are 3...  Unless, of course, the SDS1102 can be unlocked to 200 MHz - I don't know anything about that.

It's a tough choice when trading bandwidth for channels.  Like most, I spend 95% of my scope time with a single channel and I spend very little with 4 channels.  But the thing about 4 channels is if you need them and don't have them, bandwidth won't help.  The reverse is also true.

One thing that is true:  Over the last few years, Rigol has killed off the bugs in the DS1054Z.  It took some time but I guess when it became the top entry level scope they simply had to work out the problems.  It's pretty stable.  Any issues that remain are design issues and simply can't be resolved with firmware upgrades.  I'm not aware of these problems and, if they exist, they are at the edges and outside my area of concern.

I guess you could do a poll of some kind and ask which of the 3 people would recommend and which of the 3 they actually use.  I'm a huge fan of the SDS1104X-E but I have never even seen one so my vote, on that model, is pretty irrelevant.  I own the DS1054Z and I have a bit of experience with it.  Among other things, I replaced the selection encoder and the fan.  In fact, I ordered the parts the same day I ordered the scope.  These are two of the annoyances that are seldom mentioned.  The solution is documented over in the Test Equipment forum.  Some people are reluctant to make hardware changes on a brand new scope.  You CAN get along without making the changes but the selection encoder is a PITA without detents.

[tggzzz]

It looks like you are unfamiliar with typical failure mechanisms.

You might be unfamiliar with the concept of "first measure the (secondary, low voltage, isolated) output of the PSU and only poke its internals if something is wrong and it doesn't look like it's the secondary capacitors". May I suggest lurking more?

That is third.

First is look to see if there are an RIFA caps, replace them on sight. If you don't then the result is often a plume of smoke being blown out by the fan on the back panel, typically 30s-5mins after switching on.
Second is examine all the electrolytic caps to see if they are bulging or have leaked. (And look at other nearby components at the same time)
Third is "switch on and measure".

[CharlotteSwiss]

There are also activities that do not allow error, it is not contemplated... I practice climbing in my spare time, a mistake could simply be fatal
But in my life I learned that when you know you can't go wrong, you will hardly be wrong
;-)

I backpacked around India with her when she was 14, flying gliders solo before she could drive, skiing, etc. Gave her confidence to tell me when she was an 18yo, "Dad, I've just bought a flight to Australia for a 6 months trip"

As you clearly know, some risks are worth taking once you understand and control them.

after all, a life without risks is too flat. 

[ratatax]

siglent sds1202   2ch/200mhz

I have the 4ch version and it's a great scope.

2ch is fine, 4ch helped me one time to debug a SPI communication but most of the time I use only 1 ch and very basic features, just to see if some signal is here and check the overall shape...

Build quality is very good.

[CharlotteSwiss]

It would be ideal to put the local cost (including taxes) alongside the models.  For example, I wouldn't include the SDS1102 unless it was a LOT cheaper than the DS1054Z.  What's the point of 2 channels at 100 MHz unless it is a LOT cheaper than 4 channels at 100 MHz?  Then there are 3...  Unless, of course, the SDS1102 can be unlocked to 200 MHz - I don't know anything about that.

I also saw that it is a 2012 model...
I have to reduce the selection list:

-rigol ds1054z      4ch/50mhz(100hack)
-rigol ds1202z-e   2ch/200mhz
-siglent sds1202   2ch/200mhz
(siglent 4ch is out of budget)

at this point between the two from 200mhz it's just a matter of checking the specs..
but the big doubt remains only one: for my repairs, 4 ch they will change my life?
otherwise it is obvious that it is better to lose 2 ch and double the band.

the prices of the 3 products.. about are the same, small differences (for these 3 oscilloscopes it will not be the price that will make me decide..)

thanks
 

[CharlotteSwiss]

siglent sds1202   2ch/200mhz

I have the 4ch version and it's a great scope.

2ch is fine, 4ch helped me one time to debug a SPI communication but most of the time I use only 1 ch and very basic features, just to see if some signal is here and check the overall shape...

Build quality is very good.

I have no doubts, but it is out of price for me..
your opinion, however, can make me think .. maybe 4 ch are not indispensable for me
I will look better siglent 1202 ;-)
thanks

[rstofer]

exactly, the greatest difficulty lies in finding the point where to place the mass of the probe. But... looking at the scheme of the card if available,
 or a gnd screen printed on the card will be somewhere... 

There are also activities that do not allow error, it is not contemplated... I practice climbing in my spare time, a mistake could simply be fatal
But in my life I learned that when you know you can't go wrong, you will hardly be wrong
;-)

Once you find a candidate point for the probe ground, measure it to earth ground with a DMM before attaching the clip.  I don't work at higher voltages (above about +-15V) so a 10x probe is adequate.  It is rare that I use my 1x/10x probes on the 1x setting.

For the Analog Discovery 2, where the allowable input voltage is severely constrained, I bought a pair of 10x only probes such that I can't possibly get into the 1x mode.

[AVGresponding]

One thing I would say regarding probing safely, even if you have a completely isolated scope like a battery powered scopemeter for example, there is still no safe way to probe dangerous voltages.
This kind of measurement will always be dangerous, and keeping that in mind and not getting a false sense of safety by using high voltage differential probes and isolation transformers is quite important.

In over 40 years of electron herding, I've only had 1 minor mains tickle, and that happened the 1 time I didn't follow the rules.
1. It's dangerous until you've proved otherwise.
2. See above.

[CharlotteSwiss]

exactly, the greatest difficulty lies in finding the point where to place the mass of the probe. But... looking at the scheme of the card if available,
 or a gnd screen printed on the card will be somewhere... 

There are also activities that do not allow error, it is not contemplated... I practice climbing in my spare time, a mistake could simply be fatal
But in my life I learned that when you know you can't go wrong, you will hardly be wrong
;-)

Once you find a candidate point for the probe ground, measure it to earth ground with a DMM before attaching the clip.  I don't work at higher voltages (above about +-15V) so a 10x probe is adequate.  It is rare that I use my 1x/10x probes on the 1x setting.

of course, first I will measure with the dmm.
probe factor 1x10, 1x100... now for me it's total darkness.
But when I have the oscilloscope I will have to deepen this speech too...