I saw this question posted to ELECTRONICS HOBBY CIRCUITS IN FACEBOOK group: “can you tell me what is the meaning of calibration date of a multimeter and does it effect the work of a multimeter if it expires the calibration date?” The answer to this is: As all circuits will drift with time, the DMM →
Test with multi-meter that it is not short circuited. Test with capacitance meter that capacitance value is correct. If this is an electrolytic capacitor I measure ESR. With some electrolytics I charge them to nominal voltage with power supply and measure charging leakage current or the rate it self duscharges. If it is a small →
The Right To Repair is a big issue. IFixit and Louis Rossman have spread the word out how Apple making it difficult to repair products outside their service centers. On Tuesday, Apple hosted its ‘One More thing’ event, unveiling three brand new Apple Silicon Macs running on Apple’s new M1 chip “by far the most →
This is a tear-down of an interesting PIR (passive infra red) sensor found from some unknown light system believed to be powered from 230V AC. The chips used seem to be ST LM2904 low power opamp and TFK U2100 timer control chip. The sensors are PIR sensor and LDR. The most interesting part is that →
A spectrum analyzer measures the magnitude of an input signal versus frequency within the full frequency range of the instrument. The primary use is to measure the power of the spectrum of known and unknown signals. Spectrum analyzers are widely used to measure the frequency response, noise and distortion characteristics of all kinds of radio-frequency →
Facebook post at https://www.facebook.com/groups/electronichobycircuits/permalink/3743513689006646/ advertises this circuit idea: Amazing Idea With Relay & BC547 Transistor https://techsawco.com/amazing-idea-with-relay-bc547-transistor/ I see this circuit much less than amazing. “This circuit is used as voltage level indicator and short circuit protection circuit.” Voltage level indicator idea is feasible. The “short circuit protection circuit” does not live up to the promises →
Having a VNA opens up so many possibilities for RF measurements. Typical measurements are antenna matching, RF filters, impedance matching and cable loss. But it an do more. You can use it even to measure the coaxial cable length – a task that is normally performed with time domain reflectometer (TRD), an instrument I have →
Bar code 1. a method of representing data in a visual, machine-readable form 2. Computer code written or designed at bar under influence of alcohol (possibly during Ballmer Peak moment) https://xkcd.com/323/ →
NanoVNA vector signal analyzer can be used also as an RF signal generator. If you are in a hurry and need a quick & square wave signal between 50 kHz and 300 MHz the NanoVNA can come to the rescue. Just set the centre frequency of the stimulus at the value you need and a →
This posting is here to collect cyber security news November 2020. I post links to security vulnerability news with short descriptions to comments section of this article. If you are interested in cyber security trends, read my Cyber security trends 2020 posting. You are also free to post related links to comments. →