I bought one of those cheap Finrsi tablet scopes from Amazon as I needed a cheap scope to use very occasionally for basic things. Obviously I didn't want to spend a lot of money so this seemed ideal for me and the portable tablet form is quite appealing. Now a pro engineer would not entertain purchasing one of these but for a hobbyist they should be fine. However I did run into a few issues with it as in the general quality is so-so and the operation of the unit isn't without it's problems. Since making the video I would like to mention that the bandwidth is only 5Mhz on the 1x probe setting and supposedly 100Mhz on the 10x setting. I should have read that Chinglese manual. Doh. However the bandwidth is really around 20 - 25Mhz as you will see. I do encounter a lot of interference and ringing even at low frequencies which I believe is partly the scope. It does pick up noise even when nothing is connected which is kind of normal for digital scopes but more expensive models have various ways of reducing this. It also seemed to have trouble triggering from the internal 1khz calibration signal. ***The 50% auto trigger can be turned off in the system settings (I found this after encoding the video) and turning this off makes a vast improvement making the scope more usable. *** The trouble is I don't have any lab quality test gear; I can only compare this scope's performance with an older and more expensive model. I'm also used to using CRT analog scopes however the scope I use at work is a digital scope around 6 years old. I did use the same equipment to test this scope that I used with the scope I borrowed from work and didn't encounter any of the issues shown in the video if that's anything to go by. My Keysight DMM has a frequency counter built in so I was able to verify the accuracy of the scope's frequency readout which is spot on. Voltage wise, no. It's out by nearly half a volt with a 5V p-p signal input. Would I recommend this? Well depends on what you want to use it for. Basically if you want this as an instrument that can give accurate, reliable readings then no. The voltage measurement readings are way out for a start. However if you just want to check for presence of a signal or not or want it for audio use and possibly TTL logic / CMOS circuitry then maybe, yes it could work for you. But I really would save up and get something better; you need to be spending at least £300 for an entry level scope. It's a shame really as the tablet format is really good as it's portable and much easier to use on the bench without having wires everywhere. I really want to like this little scope but I just don't want to trust it. Maybe it will get future firmware updates but there doesn't appear to be any way of easily doing this unless possibly it's updated via USB? Something I could look into. ***Further update*** I've since changed my mind about sending this back. I may look at adding some sort of shielding and do some further testing with it as I believe it isn't that bad just not that good either. But there is always some doubt in my mind if this thing is showing me the right readings or not. I'm aware the voltage readings are high but I can account for that. #ads1013d ... https://www.youtube.com/watch?v=SoCd2nu_bnA

HiFi enthusiasts often "burn in" their new speakers using a variac to exercise the speaker cone which some say improves sound quality. I bring a whole new meaning to this and show what will happen if you push it too far... 18 volts was all it needed to blow these 15 watt speakers up. A short but silly video. ... https://www.youtube.com/watch?v=PIIz-BUxEco

... https://www.youtube.com/watch?v=Eh4bj1QUAHw

In my previous videos I spoke of buying some scrap electronics namely 3 x numeric wallboards and a scrolling wallboard which appear to have come from an insurance company's call centre. These units show the number of customers waiting in the call queue and how many calls have been answered. I power one up and take it apart to see what's inside, how it works and if there are any parts to salvage that could be used for electronics projects. Edit: the supply voltage to the LED modules is unregulated 9V (measured 10.8V displaying 5 zeroes) not 18 as I'd assumed in the video. The more segments that are lit the dimmer it gets; this is apparent in test mode where it scrolls through 0-9 and A-F on the displays. LED segment current is around 5mA. They also haven't used a bridge rectifier; instead used two diodes on each of the secondaries of the transformer giving half wave rectification. The DC output of the two diodes are paralleled together giving more current which is fed into a 7805 in turn supplying regulated 5V to the microcontroller and logic chips. There is noticeable 50hz flickering on the displays. Video of the scrolling message display https://youtu.be/2TwnPE5FpQI ... https://www.youtube.com/watch?v=z9JJ6MQDJj0