I picked up an Amrel PPS-2322 programmable power supply from eBay recently. You probably have not heard of the Amrel brand before as American Reliance (Amrel) no longer makes power supplies nowadays. Its power supply division was acquired by AMETEK…
In electronics, guarding is a technique typically used to prevent or minimize current leakage from a high impedance source. This method is widely used in many low level measurements especially in low current and high resistance measurements.
You can generate some pretty amazing patterns by shining a laser onto a mirror mounted on a vibrating speaker cone, a lot of people have experimented with this kind of laser show. But how about building a true laser oscilloscope…
Electrometer is a piece of highly specialized electronic test equipment. Most of us would naturally associate it with low-level measurements (e.g. low current pA, fA and high resistance GΩ measurements) only, but the situations under which you might need to…
I was quite intrigued by the S-Pen that came with my Samsung Galaxy Note 4. According to the specifications listed on Samsung’s site, the S-Pen supplied with Samsung Galaxy Note 4 he S-Pen supports 11 bits (2048 levels) of pressure…
In this blog post, we will take a look inside a 1980 vintage Keithley 614 Electrometer. While it was designed and built more than three decades ago, its performance is still pretty impressive (10 fA current resolution) even compared with…
In this blog post, I will show you a simple way of turning your Android phone into a wireless touchpad. For this to work all you need is your Android phone, an Arduino board and a HC-06 (or HC-05) bluetooth…
I recently acquired an old Beseler PM2L color analyzer. This kind of color analyzer was designed to analyze the color or exposure of film negatives at a certain location by comparing the intensity of the filtered light of each color…
I bought a Wavetek 1045 RF power meter off eBay a few weeks ago. It came with a 13787 detector which is capable of measuring RF power between -50 dBm to 10 dBm with a frequency range of 1 MHz…
Latching relay (a.k.a. impulse relay) can be turned on and off by momentarily applying a voltage across the relay coil. The relay would maintain in its last switched state without the need to maintain the coil current. In this post,…
Traveling-wave tube (TWT) is mainly used to amplify signals in the microwave frequency range. Unlike most vacuum tubes, which had largely given way to their more elegant semiconductor counterparts many decades ago, TWT is still being widely used today in…
Hysteresis can be added to a comparator circuit to improve its stability, especially when the input signal is noisy. In this post, we will examine the hysteresis characteristics of some common comparator and Op Amps using an oscilloscope.
Using software defined radio such as the popular RTL-SDR (1, 2) as a spectrum analyzer is nothing new (examples can be found on HackADay and EDN). In this blog post, we will discuss some of the do’s and don’ts when…
I have been quite happy with my fixed-up Keithley 197 5 ½ digit bench meter purchased from eBay (you can find the teardown pictures here) earlier this year. Keithley 197 has a battery pack option (Model 1978), and this option…
Arduino Due uses an Atmel SAM3X8E ARM Cortex-M3 CPU, which has a native hardware based True Random Number Generator (TRNG). In this post, we will take a brief look at how to use it in the Arduino environment and take…