A couple of months ago I joined the element14 community and decided to sign up for a Road Test which I did, for a Keithley 2110 DMM, I was not really expecting to be selected but I was which was great – so thank you element14 for the meter and the opportunity to do this review. Now while I am not planning to turn my blog into a review site, I figure that the odd review on new kit might be nice, especially if there is the opportunity to tear it down after the review – in fact I will not do any review that does not involve tearing down the kit to have a look inside.
I have specifically made this a video review so I wont write too much about the review here, you can watch the video for the detail (and the puppies too).
In summary though, I hated the display on first site and that made me want to dislike the meter too. But apart from the display, everything else about the meter, its performance, its build quality and apparent accuracy (so far as I can tell) is absolutely first class. If I had a wish list – or more to the point, if I were in charge of sales at Keithley this is what I would have done differently…
Design in a decent display, anything other than what is in there – a nice VFD, or an OLED perhaps, or even a nicer LCD if you have to
Ship a thermocouple
Make the continuity beeper useful – its way too slow response-wise
Write the software so it can be used on Windows, Linux and OSX – it really is not that hard to do
Did I say a better display?
Lui Gough also reviewed the meter and has done a really nice write-up for his review, he also tested the software and data collection aspects of the meter, you can see his review right here: Lui Gough Keithley 2110 Review
It all started when I wanted to calibrate my HP 53131A universal counter, which as it turns out probably has one of the crappiest and most disappointing standard oscillators ever put into a frequency counter, HP you should bow your head in shame….oh of course I forgot, a half reasonable oscillator is an “optional extra” when you by HP/Agilent – of course it is….anyway, on with the job at hand
If you have or want to play with an FE-5680A Rubidium Frequency Standard or an OSCILLOQUARTZ OCXO 8663-XS or a HP 53131A Counter or a Racal Dana 1999 counter or similar then this video will most likely be of interest what I am trying to get is a predicable and reliable frequency and standard for my home lab.
I guess I will let the video do the talking on this one….
Here are a whole bunch of useful links that relate to this video (there are many more too if you search around the web)
Here I describe the basic operation and topology of a Class D amplifier and then tear down an Omnitronic 1000W amplifier to have a look and see what is inside. The big advantage of a Class D amplifier is the compactness and overall power efficiency. However, Class D amps are generally not used in High Fidelity application because of the limitations in dynamic range and distortion performance that can be achieved.
Here are the specifications scanned in from the user manual.
Hope the information is of some use. Thank you for watching.
This is a quick post to demonstrate the video quality of two different cameras. This is not meant to be a side-by-side review and there is no assumption on my part that these two cameras are in the same class, because they are not. What this shows is why you might want to consider an upgrade form a high end consumer class video camera to a low end professional class video camera. The two cameras I compare are the Canon HF S21 and the Sony HXR-NX5U.
I decided to upgrade myself for a number of reasons…
More dynamic colour range
Less noise in lower light conditions
Better optics, specifically optical zoom for close-up work
Pro audio connectivity and capability
I purchased the NX5 camera at a good price at just £1,400
The outcome is pretty self evident as you will see in the video. I have made no changes to the two clips, each is a native AVCHD import directly from the SD card into Final Cut Pro X, I made no changes to the video but FCPX did have to transcode because the two camera’s shoot at different frame rates.
The quality of the HD video I am able to produce now should be much better, it will be good to see how improved the detailing is when I am zoomed into those small surface mount components…
This is a short follow-up to a video where I was recently testing a Mayyuo M9711 DC Electronic Load (See Here) and I was using an Agilent E3634A Power Supply (which I previously fixed) as a power source. When I put the DC load into pulse mode within a few seconds the E3634A PSU exploded. What I heard was a loud pop, and a flash followed by a loud vibrating 50Hz hum, by which time I was able to reach the power switch and shut it down. I switched to another supply and continued with the test of the M9711 but today I thought I would open up (once agin) the E3634A and see what damage was done and what I found is a real mystery!
Did I imagine it all? Was there beer involved? Who knows, its a mystery!
Hope you enjoyed the video, catch you next time…
UPDATE – I found the smoke source
While tidying up I thought i would have a look at the two power MOSFET’s that failed and found the IRFP260 has a very small but visible smoke vent! I have added the photo’s below, I had to take these under the microscope x10 and x30 to see it. With the naked eye it looks like a light scratch.
I have been working on various power supply projects of late and was finding that my approach to loading PSU with simple incandescent laps was limiting. What I needed was a programmable DC load so I wondered – build or buy? Because I am already working on a PSU I decided that its probably better to buy one if I can find something that was reasonable quality and at a reasonable price. So I searched around and eventually took a chance on a Maynuo M9711 DC Electronic Load. I had not heard of the company before and could not find much out about them on on the internet, what I did see what that other similar devices that cost twice as much and had a reputable brand (BK Precision for example) were so similar in form that I thought its a good chance that they are different OEM’s of the same design. I am not sure that is the case because I do not have a BK Precision to compare, but I bought the M9711 brand new from the manufacturer on the basis that this was likely the case. Was I disappointed with the purchase? we shall see…
In this video I unbox and then tear down the Maynuo M9711 DC Electronic Load so we can take a look inside and see how it works and how well its been built. I try to explain how a DC electronic load works and I present a block diagram of the Maynuo M9711 based on my understanding and the cornerstone components that I find.
The main funcional components found in the device are:
The power MOSFET (x4 in 150W model) used as the main active power device that creates the load load
Notes and Diagrams
Below are the diagrams I present in the video describing the operation of a DC Load and the basic high-level layout of the M9711. You can browse these images or download a PDF document to print out if you prefer.