FNIRSI DSO-150 – $20 Digital Oscilloscope

The main idea when I bought the DSO-150 digital oscilloscope from FNIRSI was to have a oscilloscope in our $60 electronics lab equipment kit, so the price of this equipment is a big factor on the selection. The model I received, is already a clone of the original “JYE Tech” initial version, but it is a bit cheaper than the original and as the same functions and look like.

But I wasn’t expecting to have a “really” oscilloscope that will provide reliable results that we can use in “real” projects, I was expecting, something that will work, that will allow anyone interested to learn a bit more how oscilloscopes work, but not much other than that. Boy, how I was wrong!

I choosed to buy the assembled kit, since there will be a review on the unit and I wanted that the value were the most reliable possible, eliminating from the equation some assembly mistakes I might do assembling the oscilloscope, but, if you decide to buy the DIY model, it will be even cheaper and it brings step by step instructions to assemble. All the SMD’s will be pre-assembled to make the assemply processe easier.

Let me say something first, this isn’t a full featured oscilloscope, very far from it, you have only the essencial and basic functions, but for $20 you’ll have a very functional oscilloscope that will provide you with nice results.

Let me first do a summary of specifications for this oscilloscope:

Some of the main key features are:

• ARM Cortex-M3 processor (STM32F103C8) and includes a 2.4-inch color TFT display screen
• Auto / Normal / Single trigger modes
• Available rising or falling edge trigger
• Easy to capture the moment waveform
• Observable previous waveform before trigger (negative delay)
• Can freeze waveform display at any time (HOLD function)
• Waveform metrics on the display (frequency, period, pulse width, duty ratio, MAX./MIN./AVG./Peak-Peak/virtual values)
• Waveform storage function: Will not lose the waveform after powering off

I connected the oscilloscope to the TechCorner.tv Rigol 1022Z Function/Arbitrary Waveform generator to do some real testing, the signal that comes from this unit as a very high quality and we can trust on the values generated.

In this tests I forced a 200Khz signal in to oscilloscope to test how it handle in the maximum bandwitdh usage, but to be honest, that isn’t a fair testing, a fairly common rule to analyse a signal is to use a oscilloscope with a bandwidth 3x greater than the fastest frequency of the analyzed signal, so considering this, I shouldn’t go over the 60 to 70Khz in my review, but I did, and the good news is that a 100Khz with a 10us timebase the oscilloscope handled the signal pretty well, we can even push it a bit to 120Khz, over that it will start to deform.

But if you keep the frequency around the 60-70Khz you are even able increase the timebase to someting in the order of the 50us. The oscilloscope really starts to shine in frequencies bellow the 20Khz. So, as you might already imagine, this oscilloscope server only to work in low frequencies.

In general, the response time is quite good and the signal in the screen has good quality and we can read it easily, all the metrics are available, like Vmax, Vmin, Vavg, Vpp, Vrms, frequency… you get the idea.

We still have the DSO-138, that is a older model that costs even a bit less, you can buy one for something like $15, but, after careful analysis and considering that the specifications are the the same, I think that you more well served with this model.

So, cheaper is not always better, should you buy this DSO-150 oscilloscope?

Like in live, there isn’t a simple answer and the correct one will be, it depends. It depends of what is your objective when buying an oscilloscope. Are you a begginer in electronics and wish to start learning a bit more aboute oscilloscopes and function generators? If the answer is Yes, you should buy this IF WILL NOT give a more professional use to your equipment, this oscilloscope will allow you to experiment all the basic functions you have on a desk oscilloscope, you have coupling, triggering, memory buffer, hold/run, even a waveform capture/save/recall function, so you might feel the taste of working with a oscilloscope whithout the large investment normally associated with the purchase of one.

Do you need an oscilloscope for a sporadic analysis for some task you have? Well, if if the bandwidth isn’t a limitation for the task you have in hands, so go for it, why pay more when you can use this for a time to time measurement and analysis, it works great.

If I buy this, will I after be disapointed?

Well, as said before, it depends of what you want todo. I bought this to be part of our $60 / 50€ eletronics lab kit (article not done yet), in that kit the frequency generator is able to produce signals up to 65Khz, so it will be a perfect set so test signals and learn more about them, once again, if you’re a begginer in eletronics this oscilloscope will be perfect for you. If you need something with more “juice”, I left a few suggestion bellow according the ammount of money you’re willing to spend.

So lets wrap it up, this is a really awesome unit, small, portable (you can connect a battery inside to make it really portable), it is accurate within reusonable expectations and it as a fast response, so all things consider, it seems a pretty good deal.

The thing is, you get what you’re paying, but, there is a very good racio here between, price vs features, that pends clearly for the supplied features for the price paid, you have a good quality oscilloscope for $20.

You can get DSO-150 here – 🛒 https://geni.us/3JwO79  (~ $20 / 16€)

What about alternatives?

Each case is a different case, so you might prefer to spend a bit less or more, I leave here some suggestions and you might consider a different one for your case (the list above is ordered by price cheapest to the most expensive):

Portable
🛒 DSO-138 2.4 TFT 200Khz, / 1MSa/s- https://geni.us/FZGtNv (~ $15 / 12€)
🛒 ADS2050H 2.4 TFT 5Mhz / 20MSa/s – https://geni.us/KWAOrmZ (~ $40 / $33)
🛒 1C15/5012H 2.4 TFT 110Mhz / 500MSa/s – https://geni.us/PxoYcBT (~ $68 / 57€)>
🛒 MDS120M 2.4 TFT 120Mhz / 500MSa/s – https://geni.us/ZV5Mq (~ $70 / 60€)
🛒 ADS5012H 2.4 TFT 100Mhz / 500MSa/s – https://geni.us/AnXX  (~ $75 / 65€)

Bench/Desk (entry level only)
🛒 Hantek DSO2C10 100MHz / 1GSa/s – https://geni.us/b3FG (~ $176 / 148€)
🛒 Hanmatek DOS1102 110Mhz / 1GSa/s – https://geni.us/sNwOdTp (~ $210 / 176€)
🛒 Owon SDS1102 100Mhz / 1GSa/s – https://geni.us/Eax1 ( ~ $227 / 190€)
🛒 Mustool MDS2112P 100Mhz / 1GSa/s – https://geni.us/T8SJWBx (~ $277 / 232€)
🛒 Rigol DS1102Z-E 100Mhz / 1GSa/s – https://geni.us/jFyf7 (~ $289 / 242€)
🛒 Siglent SDS1102CML 100Mhz / 1GSa/s – https://geni.us/0o36KO4 (~ $316 / 265€)

IMPORTANT NOTE: All prices in this article are for reference only and the presented values were the ones I got at the time of the research made for this article, they may be different when you consult on the respective links at the time of reading.

There is a lot of things to consider when buying an oscilloscope other than the frequency and sampling rate like memory depth, accuracy (8/12/14 bits), wfms/s, if it is upgradable, etc., this get higher importance specially if it starts to get heavy on the wallet, but the above list is just a small compilatation of sugestions for begginers and entry level oscilloscopes.

Thank you for reading this article. ❤

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