Siglent SDM3055 5.5 Digit Bench Multimeter Review

SIGLENT’s SDM3055 series is a dual display digital desktop multimeter. The SDM3055 provides a rich and powerful feature set at an excellent price. This DMM family is well suited for production testing, R&D and certification work, as well as any place where an accurate and powerful full-function DMM is needed. In the SDM3055’s design and layout, great emphasis was given on both front-panel and computer-based control of the instrument. Equipped with a 4.3 inch TFT-LCD true color LCD screen, its display resolution is up to 480 * 272. It can not only display numerical readings, but also supports histograms, trend charts, bar charts and statistics, in addition to the built-in arithmetic functions. Even when using the front-panel menu, the user can display the most important analysis results of the accumulation of time and data. This eliminates the process of drawing and statistics, and the measurement is accurate and reliable. The SIGLENT SDM3055 has a powerful testing engine, measuring speed up to 150rdgs / s, 1Gb Nand total memory capacity, mass storage instrument settings, historical data, and external U disk external storage. The SDM3055 interfaces include USB Device, USB Host, LAN and GPIB (SDM3055A). It can support VXI11, USBTMC remote control as well as interconnection with National Instruments’ LabVIEW. A SCPI command programming manual is also provided in support of remote control operation programming.It is compatible with mainstream multimeter command sets and uses the compatible language with SCPI for transmission and control.

Siglent SDM3055 5.5 Digit Bench Multimeter Review – [Link]

Teardown & Analysis of a Keysight InfiniMax III N2802A 25GHz Active Probe

In this episode Shahriar takes a close look at one of Keysight (Agilent) InfiniMax III active probes. The model N2802A offers 25GHz of analog bandwidth, 17.5pS of rise time and a total differential input capacitance of 32fF at 10k-Ohm input impedance. The front-end amplifier of this active probe is designed in an in-house InP process, the same process responsible for the front-end of the X-Series Keysight oscilloscopes.

The teardown of the probe shows the control circuitry in the main probe body built around a PIC 16F877 microcontroller coupled to a DAC, EEPROM memory and various high-current and precision op-amps for biasing. The main front-end microwave module reveals the InP ASIC and supporting microwave circuity. There seems to be a dual-path design to provide a large DC common-mode offset capability as well as a high-bandwidth.

Teardown & Analysis of a Keysight InfiniMax III N2802A 25GHz Active Probe – [Link]

TSG4106A RF signal generator unboxing and mini feature review

Always an exciting day when a new piece of equipment arrives at the lab! The basic features of the lab’s new Tektronix TSG4106A RF Signal Generator are reviewed, including a peek at some of the auxiliary signals available on the rear panel.

TSG4106A RF signal generator unboxing and mini feature review – [Link]

ESP8266 touchscreen WiFi light controller and clock


Spiros Papadimitriou has build a WiFi light controller and clock based on ESP8266:

A couple of months ago I picked up cheap WiFi-controlled LED bulbs (one among dozens of very similar devices), after seeing them at a friend’s place. This turned out to be an excuse to play with the ESP8266, which has inspired several hacks. I was overall very happy with these bulbs: decent Android and iOS apps and, compared to fancier solutions (e.g., Philips Hue or Belkin WeMo), they do not require any proprietary base stations, and you can’t beat the price! However, switching off the lights before falling asleep involved hunting for the phone, opening the app, and waiting for it to scan the network; not an ideal user experience. I was actually missing our old X10 alarm clock controller (remember those?), so I decided to make one from scratch, because… why not?

ESP8266 touchscreen WiFi light controller and clock – [Link]

Resistor Scanner Android App


Resistor Scanner is an Android app that uses OpenCV to scan resistor colour bands and determines their values.Uses OpenCV to scan resistor colour bands and determines resistor values.

Source available here:

Resistor Scanner Android App – [Link]

Raspberry PI answers, “Is the internet up?”

FullSizeRender-795244 has build a internet monitoring device based on Raspberry Pi:

It is a pretty commonly uttered question (sometimes loudly) around the home or office; “Is the internet up?” As the goto IT Support Manager around the house this can get a little tiresome. Most of the time the internet is up and it’s a user or personal device problem that can be solved with a re-boot, re-load, re-etc. Sometimes the internet is really down requiring a router and cable modem reboot or a call to the ISP. Wouldn’t a simple visual check that anyone could quickly understand be helpful? Plus, as a bonus, provide some general network health statistics with a screen print and an hourly update to a Google Drive spreadsheet.

Raspberry PI answers, “Is the internet up?” – [Link]

Voltage indicator transitions between colours


by Einar Abell @

This Design Idea gives two versions of an indicator light that changes from green to red as a battery discharges. There are many circuits that do this sort of thing, but all the ones I have seen are too complex and costly for my taste. This DI shows a method that uses an absolute minimum of low cost parts: a dual-color LED and four other parts.

Voltage indicator transitions between colours – [Link]

LTC3335 – Nanopower Buck-Boost DC/DC with Integrated Coulomb Counter


The LTC®3335 is a high efficiency, low quiescent current (680nA) buck-boost DC/DC converter with an integrated precision coulomb counter which monitors accumulated battery discharge in long life battery powered applications. The buck-boost can operate down to 1.8V on its input and provides eight pin-selectable output voltages with up to 50mA of output current.

The coulomb counter stores the accumulated battery discharge in an internal register accessible via an I2C interface. The LTC3335 features a programmable discharge alarm threshold. When the threshold is reached, an interrupt is generated at the IRQ pin.

To accommodate a wide range of battery types and sizes, the peak input current can be selected from as low as 5mA to as high as 250mA and the full-scale coulomb counter has a programmable range of 32,768:1.

LTC3335 – Nanopower Buck-Boost DC/DC with Integrated Coulomb Counter – [Link]

Mini Project: Doorbell Memory


by Jan Buiting @

Even in the Internet & Wi-Fi age where it seems irrelevant just where you are at a specific time, it’s sometime useful to know if a visitor called at your door while you were out. Who knows, it might be the DHL man with a delivery of essential components!

The little circuit described in this article can reassure you that you haven’t missed the postman’s call irrespective of whether he always rings once or twice. It’s cheap and can probably be built from parts in your junkbox.

Doorbell Memory – [Link]

USB power supply active load tester


Sasa Karanovic has designed and built a DIY USB power Supply active load tester, that is available at GitHub:

USB Power supply Active Load Tester or short PAL Tester is unit designed for testing the quality of the power supplies.
Idea was to create low-cost, precise device for simultaneous measurement of Voltage and Current drawn from the device under test.

USB power supply active load tester – [Link]