Electronics Design

The shocking power supplies

Transformerless power supplies are showing up a lot, especially in inexpensive products where the cost of a transformer would add significantly to the BOM. But transformerless power supplies are a double-edged sword. You can get yourself easily electrocuted if you don’t understand them and take proper safety precautions. Poking around in a transformerless-powered device can

Differential oscilloscope probes

By far the most used oscilloscope probes are the passive 10:1 attenuation probe. Next step in probe categories are active probes. Active probes succeed in practically eliminating reactive loading of the circuit under investigation by means of a small solid-state amplifier in the probe body adjacent to the tip. There are two main classes of

Fire and Smoke Alarm Systems

Smoke and fire alarms can save lives. The occupant and the housing company are responsible for the acquisition and maintenance of smoke alarms in Finland. It is the duty of the occupant of the flat, i.e. the resident, to buy a smoke alarm and to keep it in good working order. Smoke alarms must meet

Ethernet measurements

Ethernet over twisted-pair technologies use twisted-pair cables for the physical layer of an Ethernet computer network. Most commonly standards use 8P8C modular connectors (often called RJ-45), and supported cable standards range from Category 3 to Category 8. These cables typically have four pairs of wires for each connection, slower standards (10M and 100M) used only

Dynamic random flip memory

Row hammer (also written as rowhammer) is a security exploit that takes advantage of an unintended and undesirable side effect in dynamic random-access memory (DRAM) in which memory cells interact electrically between themselves by leaking their charges, possibly changing the contents of nearby memory rows that were not addressed in the original memory access. The

Ancient “fake RJ-45″

Who invented that and decided that it was a good idea to start to use this 10 pin RJ-45 look-alike connector? I wanted to do measurement with multimeter on UTP wiring, took a cable (left) that looked like RJ-45, but nothing worked as planned with it. Ended up butchering a real CAT6 cable (on right)

MTester LCR-T4 12864 LCD

One day I got a cheap MTester from some Chinese source. MTester is a cheap electronics component measurement device. It can detect component types and measure them. The meter has automatic detection PNP and NPN type bipolar transistors , N, P -channel MOSFET, JFET FET , diodes , two diodes, thyristors , resistors , capacitors

RLC measurements

This article is about measuring resistance, capacitance and inductance. The measurements described here talks about measuring components that not wired into any circuit. Resistors, Inductors and Capacitors are the most commonly used passive components in almost every electronics circuit. Out of these three the value of resistors and capacitors are commonly marked on top of