Over the years, I have gathered quite a few NTC and PTC thermistors. But most of them are unmarked so it would be difficult to use them in an accurate way without knowing the parameters. So I decided to build a simple circuit that can be used to trace the temperature-resistance curve, and the parameters can then be estimated using the measured data points.
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Typically a synchronous camera flash (e.g. slave flash) is triggered via an SCR. In this blog post, I will show you a circuit that can be used to trigger a secondary camera flash using an IGBT.
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Many of the modern chips such as MEMS accelerometers and gyroscopes only come in surface mount versions and many of them come in fine pitch LGA or QFN packaging. This has created a significant challenge for people who just wanted to experiment with these components. The standard soldering technique for LGA/QFN chips is reflow soldering which requires special equipment such as reflow oven and hot air rework station. Special surface mount prototyping PCBs are also needed and these PCBs, depending on the size and complexity can be quite expensive and sometimes are pricier than the components themselves.
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The drive circuits for Unipolar stepper motors are usually very simple. In its simplest form, a transistor or MOSFET is used to drive each section of the windings. With this design, the control signal must be supplied programmatically to the four windings of the unipolar stepper motor via an MCU.
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I recently bought a new digital multimeter (BK 2709B) and after a couple of months’ use, I am quite satisfied with its features and performance. So I thought I would do a quick review and share my experience here.
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Since I do not have a DSLR camera, taking photos for my projects under normal room lighting can be quite challenging. When flash is used, the pictures often turn out to be none-uniformly lit and some components reflect quite a bit of light making those portions over exposed. But if I do not use the camera flash, the pictures either turn out to be grainy due to insufficient lighting or yellowish due to the color temperature of the room lights.
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Just because you are using a true RMS multimeter does not automatically mean you should always trust the readings of your measurements. In fact, most true RMS multimeters can only offer reliable readings under certain conditions. In this post, I will examine some of the pitfalls in RMS voltage measurements and show you some concrete examples on how RMS readings can sometimes be misleading.
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Most of the multimeters do not offer resistance measurement in the milliohm range. In most meters a typically Ohm range has an accuracy of 0.1 ohm and is too coarse for measuring small resistance. Of course, some of the high-end multimeters have milliohm range and there are also dedicated micro ohmmeters for even more accurate small resistance measurements, but most of them are priced way out of the range for personal use.
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One of my computers has been unstable for quite some time now. It had been crashing and freezing up once a while in the past, but it has become noticeably worse in recent months and sometimes the computer would crash just minutes after boot up.
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One of my RSA SecureID tokens had recently expired, so I decided to do a teardown to see what is inside. While there was one such teardowns posted on EETimes a few years ago, I thought it would still be worthwhile to take it apart myself.
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Apress was kind enough to send me a copy of their recently released book “Arduino Robotics” a few weeks ago (ISBN13: 978-1-4302-3183-7, 628 Pages. Publication Date: July 18, 2011). So I thought I would read through and do a quick review on it.
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I recently dug up two sets of RF link transmitter/receiver modules from Sparkfun. I got these RF transmitters and receivers last year but have not had a chance to build anything with them yet. So I thought I would first wire up a simple transmitter/receiver to test their capabilities.
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As I mentioned a couple of weeks ago, I had been having some issues with my wireless connection at home. My suspicion was that this is an inherent issue with either 2701HG-B hardware or firmware.
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The other day, I needed to measure the AC current of my water heater without having to disconnect the wiring. Typically, you would need a clamp meter to do this. Since I don’t have a clamp meter, I thought I would just make a simple current transformer myself.
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