On eBay I bought a few of the LM2596 buck converters with constant current to use with the 10 watt LEDs I bought, and received them in the mail today. Now I don’t need a 1 or 2 ohm resistor at several watts to limit the current and waste power. Problem is it’s difficult to
(Read More…)
For decades I’ve walked to the corner of our campus to a busy street and pressed the pedestrian crossing button to go across the street to the shopping center. This has become much more frequent since the Starbucks moved into the shop on the corner, and the guys have to have their caffeine fix (I
(Read More…)
OMG, I was watching the news this evening and they showed a boulder falling onto the road, and nearly crushing a car in Taiwan (If the link doesn’t work search for boulder taiwan). It’s incredible! It looked like the boulder threw some other debris onto the road before it hit, and the debris pushed the
(Read More…)
I received this big, beautiful vase for a present, and it is slim and tall, about two feet or 0.6 meters tall. Its base is narrow and it easily would fall over if it was not fastened down to something. I got an idea that it would make a great lamp base. I’ve watched Antiques
(Read More…)
These schematics are from a RADAR Data Processing System used in the military in the early to mid 1960s. They show how the vacuum tube and transistor versions were designed. I’m blogging them to show that the blocking oscillator circuit, similar to the Joule Thief, has been around for a very long time.
I recently watched the Frontline episode on PBS that dealt with criminal prosecutions based on fingerprints, bite marks and other evidence. The FBI claimed that the fingerprint system is infallible and that no two fingerprints are the same. The FBI arrested a guy in the U.S. for a crime that happened in Europe, on the
(Read More…)
Often an experimenter needs a variable resistance and adds a trimpot to the circuit. For instance I want a resistor that can be varied between 220 and 330 ohms. The easiest solution would be a 220 ohm resistor and a 100 ohm trimpot in series. But I don’t have a 100 ohm trimpot, which is
(Read More…)
QS sent me a link to a design that supposedly uses four Peltier tiles to generate enough light to be used as a flashlight. Apparently there are no further details. There are some points to ponder in what the link said: It used the word ‘objective’, which means it’s something that they hope to achieve,
(Read More…)
This is a photo of the PCB inside of the battery box of the LED macro ring light. It has two AA cells, which can’t put out high enough voltage for the white LEDs, so the circuit on the PC board boosts the voltage. This draws nearly 3/4 of an amp from the two AA
(Read More…)
I said I’d soon be posting another one of Chris’ KD4PBJ’s projects. This is a pic of the exciter he built lighting up a small fluorescent tube. It also lights up a CFL bulb. Notice that it doesn’t use any wires, it just radiates a strong field and the light just gets excited! Another trick
(Read More…)
