Why are switchable 1x/10x probes the 'standard'? - Page 1
Forum section: electronics / testgear

author: Fungus
author_rank: Super Contributor
timestamp: August 14, 2016, 10:21:39 am
content: Why are switchable 1x/10x probes supplied as standard?It seems like a stupid decision.1x mode confuses newbies and it's hardly ever needed (I can't remembereverusing it - what situations would you actually need it for?)They're easy to switch accidentally (possibly wrecking your 'scope if you're poking around mains power).I imagine they're a nightmare if you have family. Kids love things with little switches on them.Why are they supplied as standard? A fixed 10x probe seems much more sensible and a 1x probe can be had for $10 if you really need one.

author: setq
author_rank: Frequent Contributor
timestamp: August 14, 2016, 01:04:51 pm
content: This is a bugbear of mine too. I tend to live off second hand kit as I'm not a professional which almost always comes with no probes at all, so it's off to ebay for some cheap Chinese ones. They ALL seem to be switchable 1x/10x probes when all I want is three 10x ones. I use a bodged up FET probe from Troubleshooting analog circuits as a 1x if I need it as a standard 1x probe is just death by capacitance. Please someone point me to some 10x ones without switches. What is even more frustrating is sometimes the switch gets dicky or you knock it. If it gets dicky, the ends get snipped and the cable is chucked in the junk box for some RF patch some day. I'm on about probe 6 now due to this.As for kids, you're right there. I have a scope, two power supplies, a couple of bench meters and a function generator on my bench, temporarily in the hall. I keep all really dangerous stuff in the kitchen i.e. soldering so there's perhaps 30v floating around max. The scope is a Philips PM3217 which has more traps and pitfalls than a nuclear power station.. On a positive note though I know that scope inside out thanks to their incessant meddling with it so you can win on that front.

author: Fungus
author_rank: Super Contributor
timestamp: August 14, 2016, 01:14:30 pm
content: Quote from: setq on August 14, 2016, 01:04:51 pmhttp://www.ebay.com/sch/i.html?_nkw=10x+probe

author: setq
author_rank: Frequent Contributor
timestamp: August 14, 2016, 01:31:55 pm
content: Quote from: Fungus on August 14, 2016, 01:14:30 pmI'm in the UK. It's just chinese 1x/10x crap saturation or overpriced Tek probes. See:http://www.ebay.co.uk/sch/i.html?_nkw=10x+probe

author: Vgkid
author_rank: Super Contributor
timestamp: August 14, 2016, 02:44:14 pm
content: Probemaster makes some fixed ones. I own a few.http://probemaster.com/4900-oscilloscope-probe-basic-kit/

author: setq
author_rank: Frequent Contributor
timestamp: August 14, 2016, 02:55:11 pm
content: Excellent. Now to see if I can find some of them in the UK. Thanks for the pointer.

author: nctnico
author_rank: Super Contributor
timestamp: August 14, 2016, 03:00:45 pm
content: Every now and then I switch to 1x for looking at small signals. Sometimes I use a probe switched to 1x together with my differential probe for better signal integrity.

author: Muxr
author_rank: Super Contributor
timestamp: August 14, 2016, 03:09:04 pm
content: Quote from: Vgkid on August 14, 2016, 02:44:14 pmThat 4906-1 looks nice, and for $73 not a bad price either.

author: georges80
author_rank: Frequent Contributor
timestamp: August 14, 2016, 05:07:23 pm
content: Quote from: Muxr on August 14, 2016, 03:09:04 pmI have a 4905-2K and they are nice probes and the extra probe accessories can be very handy for certain probing tasks. It is the primary probe I use on my agilent 2024a since I don't like the agilent probes that came with it (clunky/large probes). The agilent probe head is nearly 2" longer...My scope typically has only 2 probes connected, ch1 the 4905 and ch2 an agilent (because it was free), the other 2 channels go to my current probe and differential probe. Maybe I should ebay the other 3 brand new agilent probes and buy some more 4905-2 probescheers,george.

author: tatus1969
author_rank: Super Contributor
timestamp: August 14, 2016, 05:30:12 pm
content: there is a very good reason for doing that:when switched to x1, the probe has significantly more input capacitance (the cable capacitance goes 1:1 to your test signal) and highly reduced bandwidth. But you have no signal attenuation, and can measure small signals.when switched to x10, then the signal is attenuated (not amplified) by a factor of 10. Your scope needs to compensate this by amplifying it again, which adds noise and does not allow measuring very small signals. But the attenuation also drastically reduces the input capacitance and increases the signal bandwidth of your probe. In fact, if you have a 100MHz rating written on your probe, then this is true *only* for x10 setting.

author: joeqsmith
author_rank: Super Contributor
timestamp: August 14, 2016, 06:38:08 pm
content: The first scope I ever bought new was made by Hitachi and had switched probes. I used the 1X many times looking at low frequency low amplitude signals. This was a big step up from my first analog scopes and home made probes. All of my higher cost probes are fixed but the low cost ones I use from Hantek (PP-150) are switchable.Probing at my home can be anything from coax to capacitor and resistive dividers. I have never damaged a scope's front end which is a bit surprising. Seeing my first scopes were tubes, I am guessing they were a little more forgiving to my lack of skills and knowledge.A friend of mine had a scope (we are talking something from the dark ages) which had an AC/DC/Ground rotary switch on the front. The input connector looked more like some sort of audio jack. Anyway, when you selected ground, it literally shorted out the input to the scope. With a section of coax for a probe, he had some stories to tell.It's been fairly easy to train the animals on proper lab etiquette. Tail swooshing is always excused.

author: vk6zgo
author_rank: Super Contributor
timestamp: August 15, 2016, 01:21:18 am
content: Switchable probes used to be more the exception than the rule.Most places I worked had several 10x probes & one 1x probe.Of course,in those days,you were usually using Tektronix or HP stuff,plus the very occasional BWD or Telequipment.I believe Tek & HP did make a few switchable probes,but I never saw such things.1x probes can be very useful in situations where you are trying to see low level,fairly low frequency signals in a strong VHF RF environment (TV sites).OK,later 'scopes have 20MHz switchable response,but not all 'scopes had that.I,& many of my contemporaries also used Oscilloscopes to look at DC voltages,as it was a lot easier than shuffling back & forth ,CRO to DMM & vice versa.Looking at 5v or 15v supplies with 1x is not a major drama,as they are not high impedance circuits.In fact,using the old style 1A5 plug ins on a Tek 545B,you could look for ripple on tube HT supplies with the plugin in DC input mode.I have noticed with the "El Cheapo" 1x/10x switchables,that what seems to happen is that the external part of the switch falls off,but the internals still work,& can be switched with a small screwdriver.When that happens,I usually switch them to 10x & leave then there.If I need 1x,I have a clunky old Tek probe.Old Tek/HP 1x probes are usually in better condition ,as they are not used as much as 10x ones are.

author: Muxr
author_rank: Super Contributor
timestamp: August 15, 2016, 01:46:41 am
content: Quote from: joeqsmith on August 14, 2016, 06:38:08 pmthat's pretty funny

author: Keysight DanielBogdanoff
author_rank: Unknown
timestamp: August 19, 2016, 07:15:32 pm
content: Quote from: Fungus on August 14, 2016, 10:21:39 amA scope manufacturer (not HP/Agilent/Keysight) started including them as the standard probe and made a big marketing stink about it.There are definitely benefits:Quote from: tatus1969 on August 14, 2016, 05:30:12 pmAs a general rule at 10:1 attenuation, your internal amplifier noise is 10x what it would be at 1:1.

author: tszaboo
author_rank: Super Contributor
timestamp: August 19, 2016, 09:01:47 pm
content: Quote from: nctnico on August 14, 2016, 03:00:45 pmYes and debugging/verifying SMPS circuits, where the x10 probe is full of noise and you will have the 20Mhz bandwidth limit on anyway.And debugging anything noisy where you will turn on the bandwidth anyway.And using it as the magic wand, which solves issues with your circuit if you poke it at the right place. So you will know, that some picofarads will be needed on some nasty pcb trace.I use the x1 as default. Only switch, when I need to look at digital stuff, so hopefully never.

author: zapta
author_rank: Super Contributor
timestamp: August 20, 2016, 06:13:23 am
content: Quote from: setq on August 14, 2016, 01:04:51 pmAnother option is to use switch lock like this onehttp://www.thingiverse.com/thing:1727065