A battery can be regarded as an ideal voltage source in series with an impedance, which is called internal resistance. When the battery works, the voltage output is lower than the open-circuit voltage (abbreviated as OCV). The difference is the voltage drop caused by the internal resistance. Internal resistance represents the battery’s limiting factor to →
The flickering of the LED light bulbs can be a problem for some people and also when making video/film. Some LED light bulbs flicker noticeably when new, some do not flicker noticeably. In home lighting applications, flickering LED lights can be particularly bothersome in areas such as the living room or bedroom where people often →
Broken USB cables. This USB-A to USB-C cable from Biltema was cheap, but the quality and robustness could been better. I have several cables that have all broken exactly like this. I don’t remember many other USB cable that would have damaged like this. If they had used decent construction in the USB C connector, →
I have been interested in getting a multimeter that can connect to a smart phone for some time. I write on multimeters that connect to a smartphone in my blog already in 2014. I finally bought one: UT60BT. This UT60BT multimeter is feels reliable and feature-packed tool. This meter connects to your smartphone via Bluetooth, →
I got from sale some probes for multimeter: Universal Multimeter Test Hook with Miniature Plane Type IC Clip and Probe Needle Versatile for High Pressure Differential Applications Accurate Readings and Secure Connectivity One end those probes have has a small clip that works with small electronics. The other end fits normal multimeter probes (2 mm →
R413D08 is a 8 channel relay control board that is designed to be controlled from your computer through through the RS-485 interface. The idea is that this board takes control commands from computer (MODBUS or AT commands) and gives out signals that can control relays. The output from this card are 5V TTL level signals →
Here is a Modbus RTU Relay Module I got some time ago, but waited for time to test it. It is a Modbus 2-channel relay module is expected to be very useful device for making something Modbus compatible. It should be suitable for industrial control equipments and/or component in IoT applications. Description: Specification: Power Source: →
I had ordered months ago a XY-MD02 Temperature and Humidity Transmitter Detection Sensor Module Modbus SHT40 Temperature Sensor from some Chinese source (it is available from many on-line shops). Now I had finally some time to test it. Parameters: Product name: temperature and humidity transmitter DC power supply: DC 5V-30V Output signal: RS485 signal Temperature →
Here is a look at old KEMO M087 LED tester module (the original M087 is discontinued product but there is a newer different looking M087M product. With the aid of this test module it is made possible to carry out tests with all kinds of light emitting diodes in order to check function, brightness, colour →
Have you ever wondered about how safe your place or position is regarding electromagnetic and magnetic fields? An EMF meter is a scientific instrument for measuring electromagnetic fields (abbreviated as EMF).EMF meters measure fluctuations in electromagnet fields. Measurements of the EMF are obtained using an E-field (electrical field) sensor or H-field sensor (magnetic field). I →