I picked up a Marconi 2305 modulation meter off eBay the other day. As the name indicated, a modulation meter is used to measure the modulation characteristics of a source signal. The Marconi 2305 is capable of measuring amplitude/frequency and phase modulated signals from a few hundred kHz all the way up to 2 GHz.
The Marconi 2305 was built sometime between the late 70’s and 80’s. It is a pity that the iconic British Marconi Instruments went under in 1998 and had since changed hands a couple of times.
I just picked up a LogiMetrics A300/S 2 GHz to 4 GHz (S band) traveling wave tube amplifier (TWTA) on eBay. I had done an extreme teardown of an HP 493A TWTA a while ago and it was quite fascinating to see what’s inside of a TWT. This LogiMetrics A300/S was made from the late 70’s and unlike the HP 493A it was made entirely using solid state devices (e.g. transistors and ICs), the TWT itself of course remains a vacuum tube.
Kerry Wong did a teardown of an old analog piezoelectric vibrating gyroscope:
Gyroscopes nowadays are based on micro-electro-mechanical systems (MEMS) technology. They are low cost and extremely miniaturized. A device combing both a three-axis gyroscope and a three-axis accelerometers (sometimes these devices are referred to as 6DOF devices) such as the MPU-6500 for example can be had in a QFN package as small as 3 mm x 3 mm and under 1 mm in height. Before these MEMS devices gained mainstream popularity however, larger piezoelectric vibrating gyroscopes were used in many consumer electronics devices.
After a 4 year run the dashcam on my car stopped working: a fault seems to have developed in the power system. It was mounted to the window by what I thought was just a simple mechanical mount… on further analysis it became clear that the GPS receiver was part of the mount (makes sense as the user normally glues this part to the windscreen).
I have made many electronic loads in the past. For instance this simple harddrive cooler housed small dummy load, this more sophisticated constant current/constant programmable load and this heavy-duty electronic load that is capable of sinking over 1kW under peak load. In this blog post though, I am going to take a look inside an Array 3711A DC electronic load I recently purchased on eBay. You can find a video of this teardown towards the end of the post.
Typically, a lab power supply can only operate within a single quadrant. Take a positive voltage power supply for example, it can only output or source current. If any attempt is made trying to sink current into the power supply by connecting a voltage source with a higher voltage than the output voltage of the power supply, the power supply would lose regulation since it cannot sink any current and thus is unable to bring down and regulate the voltage at its output terminals.
The Agilent 66312A dynamic measurement DC source however is a two-quadrant power supply, it not only can source up to 2A of current between 0 and 20V, but also can sink up to 1.2A or 60% of its rated output current as well. Although lacking some key functionality of a source measure unit (SMU), Agilent 66312A can nevertheless be used in similar situations where both current sourcing and sinking capabilities are needed.
Before the advent of optical mice, the go to technology was a steel ball which moved two drive shafts to indicate position.
A good example of this is this Microsoft “Intellimouse”.
As expected the electronics are built around a small micro controller
My original plan was to find a replacement LCD and restore the unit to its original full functionality. But the LCD used in this unit is likely specifically made for the 169X series of power supplies and through some initial research I realized it would be extremely difficult to get hold of unless I could find a donor unit with a functional LCD inside. After I received the power supply, I realized that it had more issues than just the broken LCD itself. During my initial testing, I found that the output would not reach higher than 10 to 11 volts even with the over voltage protection set to the maximum value (20.5V). So clearly I have more homework to do, and for the time being let’s simply strip it down and see what’s inside.
I recently purchased a BSide ACM03 Plus clamp meter so that I could do some high current measurements for my tab welder project. This meter can be bought on eBay for around $25, which makes it one of the cheapest Hall effect clamp meters on the market that is capable of measuring both AC and DC current.
Since this is such a cheap meter, I wasn’t expecting much. But it actually feels really sturdy in hand and the construction looks reasonably solid, which is certainly a good start. It came with a nice little black pouch inside a non-descriptive cardboard box. It even includes a decent product manual.