Collaborate Disseminate
During the first half of the 20th century radio technology was booming, albeit restricted by the vacuum tube technology of the time which made radios cumbersome in size and power …read more Continue reading Making a Crystodyne Radio With Zinc Oxide and Cat’s Whiskers
In the first part of this series, we took a look at a “toy” negative-differential-resistance circuit made from two ordinary transistors. Although this circuit allows experimentation with negative-resistance devices without the need to source rare parts, its performance is severely limited. This is not the case for actual tunnel diodes, …read more
Continue reading Fun With Negative Resistance II: Unobtanium Russian Tunnel Diodes
The concept of negative resistance has always fascinated me. Of course, a true negative resistance is not possible, and what is meant is a negative differential resistance (NDR). But of course knowing the correct term doesn’t do anything to demystify the topic. Negative resistance sounds like an unusual effect, but …read more
Continue reading Fun With Negative Resistance: Jellybean Transistors
People talk about active and passive components like they are two distinct classes of electronic parts. When sourcing components on a BOM, you have the passives, which are the little things that are cheaper than a dime a dozen, and then the rest that make up the bulk of the cost. Diodes and transistors definitely fall into the cheap little things category, but aren’t necessarily passive components, so what IS the difference?
That’s the list. Those are your passive components. Well, it’s not that easy. Also add in a bunch of types of …read more
When you leaf through a basic electronics textbook, you’ll find chapters describing in detail the operation of the various components. Resistors, capacitors, inductors, and semiconductors. The latter chapter will talk about P and N type regions, introduce us to the diode, and then deal with the transistor: its basic operation, how to bias it, and the like.
Particularly if your textbook is a little older, you may find a short section talking about the tunnel diode. There will be an odd-looking circuit that seems to make no sense at all, an amplifier formed from just a forward-biased diode and a …read more
Continue reading Negative Resistance: It Shouldn’t Make Sense!
It is so often the case with a particular technological advance, that it will be invented almost simultaneously by more than one engineer or scientist. People seem to like a convenient tale of a single inventor, so one such person is remembered while the work of all the others who trod the same path is more obscure. Sometimes the name we are familiar with simply managed to reach a patent office first, maybe they were the inventor whose side won their war, or even they could have been a better self-publicist.
When there are close competitors for the crown of …read more
Continue reading Do You Know Oleg Losev? An Engineer Tragically Ahead of His Time
If you have ever entertained yourself by reading comprehensive electronic-theory textbooks you’ll have seen references to technologies that sound really interesting but which you will rarely hold in your hand. They may be dead-ends that have been superseded by more recent innovations, or they may be technologies that have found uses but in other fields from those in which they originally showed promise. What if you could take these crazy parts and actually build something?
[Fedetft] has an interesting project that combines two of those intriguing textbook references, he’s created a thermopile that lights an LED through an inverter whose …read more
Continue reading A Ridiculous Way to Light an LED: Candle-power
