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 →
I have Hung Chang HC-F100L multifunction counter that I bought few decades ago. I planned to do a teardown post of it some day, but someone else did it first. Korean Multifunction Counter Teardown https://hackaday.com/2024/07/07/korean-multifunction-counter-teardown/ [Thomas Scherrer] likes to tear down old test equipment, and often, we remember the devices he opens up or — →
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 →
I got a mains power (230V AC) surge protector for teardown and analysis. This one is designed to be installed to DIN rail on the small electrical distribution panel or inside electrical equipment. This one was in original package but already the indicator showed that it was broken. This protector protects against voltages above 320V →
Here is a tear-down of a mains powered (230V 50 Hz) timer switch. Let’s look how this is built. Many mains power timers use mechanism that has mains powered syncronous motor, but this is different. This one has a electronic clock timer in it. There seems to be one clock IC with a crystal (around →
I accidentially killed my favorite multimeter that had served me well for a long time. I was verifying another multimeter by comparing it’s reading to measurement made by this meter (that was checked to be accurate with a calibrator in 2020). My meter just went dead. New battery did not help. Any repair tips or →
The Acer Nitro 5 is a budget gaming laptop. This model was just around 4 years old. This computer was hit with two problems: the computer does not turn on and the screen hinge was broken. Open the laptop by removing the bottom of the computer. It had many small screws that I had to →
I got few years ago this cheap USB powered mosquito trap. The idea in it is that Blue/UV light gets the mosquitos to go near the device, and then the device sucks them away. This product was cheap, but was not very effective. When I tried this device this summer, it did not seem to →
Mosquitos don’t just whine in your ear and drive you mad with itching, but they also spread disease to more than 700 million people every year. Mosquitoes are attracted to carbon dioxide as well as the warmth and humidity you’re giving off. There are many different types of mosquito repellent. From zappers to catchers to →