Photo from ?? Thanks, Mike Guerrucci. This is a simple device. That means it’s just a buzzer and a battery. And it has a super sensitive magnetic switch. This detector is always open until it is disturbed by a magnetic field. They call it a magnetometer. One way to make this is to use a
(Read More…)
So many ideas about the future promises of nuclear fusion power, how it will affect the world. Will nuclear fusion ever become a reality? It remains to be seen. In the meantime we will have to make do with renewable energy, mostly wind and solar. The goal is to greatly reduce use of fossil fuels
(Read More…)
From FB group Jan 19 Joe Haupt In the ’80s I occasionally did work in an electrical room on campus that had a 7 foot slide rule that had been removed from the classroom. It was there for years, but the fire inspectors would make us keep the junk from accumulating in closets, so it
(Read More…)
I started thinking about how the makers of transistors sort the different grades of transistors as they’re manufactured. I thought that a reasonable analogy would be similar to how a farmer might sort the fruit he harvests. Here’s what I came up with.The farmer starts with the fruit his workers have gathered. The fruit is
(Read More…)
from FB group Building Transistor Radios 2018-08-22 Olek Kopyto I recently did some tests on 2N3904s I got from Mouser and from a Chinese eBay seller. The ones from Mouser had a current gain of right around 200, right in the middle of the 100 to 300 gain range according to the data sheet. The
(Read More…)
From FB group Hobby Electronics When a manufacturer purchases parts for the product they are making, they expect to receive what the engineers department had specified in the department’s documents. When the parts are received, the Quality Control department is supposed to check to see if the parts received meet the engineering documents. I know
(Read More…)
From my FB comment Some comments say measure with a meter, but fractional ohm resistors don’t measure, or barely measure with the typical ohmmeter. Instead, you should be giving better advice. You should use the device between your ears to find the resistance. The resistor should be put in series with another resistor of
(Read More…)
From YT reply to Neilgn 2017-08-20 Take any NPN transistor and measure the gain, and write it down. Then put a 1k resistor in series with the transistor’s emitter and connect the emitter to positive and base to negative of a power supply. Adjust the voltage until 2 or 3 volts are across the 1k
(Read More…)
My blog was down for a few days. The hosting svc had to consolidate its IP blocks and give some back to the RAR, so my rustybolt.info was pointing to the wrong IP. I was looking out the patio door at the radiometer on the table outside, watching it spinning like crazy in the really
(Read More…)
