What cheap handheld scope to buy with good triggering - Page 1
Forum section: electronics / testgear

author: florkk
author_rank: Contributor
timestamp: November 08, 2019, 06:42:06 pm
content: hello, anyone can recommend some cheap scope with good triggering? it must work ac/dc up to 600-800V must have trigger that can trigger fast and non repeative signal. it will be my first scope , so i dont want spend too much, prefer some china handheld scope most for automotive, but not only. i can find something good for ~100$?

author: tautech
author_rank: Super Contributor
timestamp: November 08, 2019, 06:56:40 pm
content: Quote from: florkk on November 08, 2019, 06:42:06 pmWelcome to the forum.600-800V working is immediately the first problem for cheap !100x probes are required to safely do this which alone is most of your budget.For what you want to spend your requirements are unrealistic.

author: Gyro
author_rank: Super Contributor
timestamp: November 08, 2019, 07:03:55 pm
content: A very similar request from just the other day...https://www.eevblog.com/forum/beginners/budget-handheld-scope/As tautech says 600-800V is a problem for ANY scope (in fact cannot be solved by the scope choice), you are looking at properly rated and safe probes which will be expensive.P.S. You haven't said anything about bandwidth requirements.

author: Ice-Tea
author_rank: Super Contributor
timestamp: November 08, 2019, 07:19:43 pm
content: Define "budget"? The THS720P with P5102 probes would do fine.https://www.ebay.de/itm/143412059187Yes, that's my listing

author: Gyro
author_rank: Super Contributor
timestamp: November 08, 2019, 07:26:01 pm
content: In the OP he says $100. Maybe you can do him a 'Best offer'

author: Ice-Tea
author_rank: Super Contributor
timestamp: November 08, 2019, 07:52:56 pm
content: Oh good grief, totally missed that. For that he can have about a single probeBluntly, don't think he'll be doing much safe probing for that budget..

author: Syntax Error
author_rank: Frequent Contributor
timestamp: November 08, 2019, 08:24:51 pm
content: @florkk : It all depends on your budget.You say a Chinese handheld, is there anything that you have in mind?There are plenty of highly specified traditional tube oscilloscopes on ebay; Agilent, Phllips, Kenwood, Hatachi, Tektronix and Hameg, just to name a few solid brands that can be won for $150 to $250. Many sellers include the probes too. Being traditional 'scopes, they will have high probe voltages, but typically 400V.If you want something very portable and new, may I suggest a USB scope? Pico Technologies make a very capable range, some are designed for automotive work. But the $100 scope is limited to a 20V maximum input.https://www.picotech.com/products/oscilloscope

author: florkk
author_rank: Contributor
timestamp: November 08, 2019, 08:37:47 pm
content: this high voltage is peak voltage from charge coils, so it indeed have that many volts but for fraction of second

author: tautech
author_rank: Super Contributor
timestamp: November 08, 2019, 10:03:33 pm
content: Quote from: florkk on November 08, 2019, 08:37:47 pmYes I've done this too and measured some 400V which is possible with 10x probes as the frequencies of traditional spark ignition systems is very low, only a few 100 Hz at max. High frequencies on the other hand, the probe V rating drops to quite low values so one must take care when using 10x probes at elevated voltages.A modern mains powered DSO has no problem with this and as they draw just a few Watts they can be powered in the vehicle with a cheap 12V inverter.

author: I wanted a rude username
author_rank: Frequent Contributor
timestamp: November 09, 2019, 01:58:13 am
content: Quote from: tautech on November 08, 2019, 06:56:40 pmThe "Hantek T3100" style probes are apparently OK according to Amazon reviews, and cost < $15 including shipping. If 200 kHz bandwidth is enough, thesuper budgetoption would be one of these coupled with a DSO150 plus a 9 V power supply ... total cost maybe $40.

author: Microcheap
author_rank: Frequent Contributor
timestamp: November 09, 2019, 02:19:42 am
content: Quote from: florkk on November 08, 2019, 08:37:47 pmI have a Hantek 2d42 handheld, I think it is one of the few options that will fit in your budget, but that's a Hantek, so expect some software "quirks". They also have an automotive version of this handheld already bundled with the cables and attenuator to probe the ignition coil (HT25 and HT201):http://www.hantek.com/en/ProductDetail_16175.htmlbut you can get the cheaper 2C42 (with no function generator) or 2D42 (with function generator) and buy the cables separately.

author: florkk
author_rank: Contributor
timestamp: November 09, 2019, 05:55:13 am
content: this hantek seems nice, and it have two channels, i will look on to it, btw i cant not remember what triggering function is when you get rapid spike voltage and you want to catch them, in past i get some cheap dso but it cant trigger and show single waveform, like you connect it to something that dont output anything, and when you turn it on it output on random time some signal and stop , and you want dso catch this signal and show it. triggering simple am i right?

author: BravoV
author_rank: Super Contributor
timestamp: November 09, 2019, 07:03:46 am
content: As many mentioned, forget about your mission with only $100 budget on what your want at the 1st post, its simply unrealistic. And you don't even know what bandwidth you need.

author: Microcheap
author_rank: Frequent Contributor
timestamp: November 10, 2019, 12:30:50 am
content: I'm not sure if it's what you need but I can pick up the secondary waveform of the ignition with the handheld and a cable like the ht25.

author: Circlotron
author_rank: Super Contributor
timestamp: November 10, 2019, 01:50:29 am
content: Quote from: tautech on November 08, 2019, 10:03:33 pmYeah, I popped a 400V rated probe while measuring the primary side of an ignition coil that was being driven by a capacitor discharge ignition. The pulse rise time was -450V in 1uS and if I had of looked at the max voltage vs frequency graph on the probe instructions first... 100:1 probes on the other hand are fine for this.

author: florkk
author_rank: Contributor
timestamp: November 11, 2019, 12:09:41 am
content: i think i order 2c42 so for high voltage i must use ht25? seems coil outputs in KV , and in ranges up to 400-600v it will be enough to use 10x probe?

author: cliffyk
author_rank: Frequent Contributor
timestamp: November 11, 2019, 01:19:08 am
content: Quote from: florkk on November 11, 2019, 12:09:41 amDo not attempt to monitor the secondary of ignition coils via a directly connected anything. Monitor the primary side which mimics the waveforms of the secondary.Here is a typical spark event captured on the primary side the ignition coil;The 250 VDC spike is what is required of the coil's output to ionize the plug gap--on the secondary side this would be 12 to 15 kVDC. THe flatter and lower voltage portion is the actual plug firing event, 600 V to 1.5 kVDC on the secondary side.This capture is the primary side of a COP on a 2003 Mustang GT V8;Note that the engine control system fires the plug three times in rapid succession. It does this to ensure a full and complete burn at idle, and up to 1100 RPM or so.THe Hantek HT25 is an inductive pickup probe, it's output to the scope is < 1.0 V -- BTW, you can make one of those with a copper pipe cap and a piece of PVC pipe..Here's A YouTube video of a fellow making that pictured above. There's not one bit of magic involved.And here, FWIW is a capture of a primary side firing event of a 2003 Suzuki Burgman 400 maxi-scooter's ignition coil; it is a near classic waveform of a spark plug's firing.:It was captured on a test bench, the coil being activated by an ignition coil test apparatus of ny own design (shown here with an aftermarket "high-performance" Ford COP and an air-gap HV tester):A good coil will fire strongly across a 15 to 16 mm air-gap; if the best one can do is 10 to 12 mm,lI start to suspect a bad coil.Here's an .mp4 video of a test.

author: florkk
author_rank: Contributor
timestamp: November 11, 2019, 11:39:45 am
content: last question it is wort for me to pay extra for awg? can it be useful in automotive ?

author: cliffyk
author_rank: Frequent Contributor
timestamp: November 11, 2019, 01:59:12 pm
content: Quote from: florkk on November 11, 2019, 11:39:45 amYou have me at an advantage here--what is "awg"; to me it is either American Wire Gauge or Arbitrary Waveform Generator...

author: Microcheap
author_rank: Frequent Contributor
timestamp: November 11, 2019, 03:51:02 pm
content: i think he refers to the Arbitrary Waveform Generator that is one of the functions of the Hantek2D42.I'm don't work as a mechanic so I can't say if a function generator is really useful for you, maybe use square wave pulses to test sensors?

author: cliffyk
author_rank: Frequent Contributor
timestamp: November 11, 2019, 04:14:12 pm
content: Ah...I would not pay extra for a scope with an AWG built-in. Most(maybe all) automotive diagnosis and repair involves monitoring signals generated by the control system(s)....

author: florkk
author_rank: Contributor
timestamp: November 15, 2019, 09:55:00 pm
content: i order 2c42, since it can be easy updated to even 2d82 auto version, btw if someone interested in hantek 2000 series , i found Russian forum with big thread about this scope with mods.https://forum.nickbel.com/index.php?&topic=5.915

author: Microcheap
author_rank: Frequent Contributor
timestamp: November 15, 2019, 11:29:28 pm
content: There is also a thread in this forum about this series of handheld scopes:https://www.eevblog.com/forum/testgear/hantek-2c422c722d422d72/