20 minutes of playing around with junction field effect transistors (JFETs). Happy new Year!
By Julian
Youtuber, shed dweller, solar charge controller aficionado
Good morning all…
Youtuber, shed dweller, solar charge controller aficionado
This site uses Akismet to reduce spam. Learn how your comment data is processed.
Absolutely LOVE this! ❤ I've been using 2N3819s quite a lot lately but I was curious about symmetrical JFETs, also. I'd also like to ask, Julian, if the solder less breadboard is made by Lego? Gr8 upload, very enlightening easy for me to follow. Thanks. 🙂
Thank you.
im just getting into electronics and im really enjoying it so far. i bought a strip of those MMBJ201 SMD and a pcb adapter board . im using them to act as the tubes in a marshal Plexi amp but in a pedal form and they sound really good. really good dynamics . if i pick my guitar softly its completely clean sounding no distortion, if i hit my strings a little bit harder it starts to break up with some distortion in a really nice sounding way. i very much enjoyed your video on these Jfets id like to learn more about all my transistors .
How about a lightning detector? that would ping and light a lamp with a lightning flash? I thought of a little "Haunted House" that would flash along with a real storm, just to let you know a storm was brewing.
On thhe subject of JFETs, you should do a video on lambda diodes. It's basically just a P type and N type jfet in series and has an operational region with negative resistance. Sort of like a tunnel diode, but higher voltage.
Many thanks Julien. This is one of my favourite videos on YouTube. I love it. Seriously. Great stuff.
The biggest problem I have with these devices is how much parameter spread you get, even with the same part number from the same batch by the same mfr…
those are some pretty cool electric croutons you got there buddy
How to make +-12V supply from a single 1A 12v wallwart? In my Behringer Neutron the PSU is working from this little 12v wallwart. Is that some kind of inverting IC or it can be simpler?
If you ever get back to playing with JFETS try the MPF102 she is highly sensitive, I have been building stand alone ghost detectors with these JFETS for some time now, they are very simple consisting of the JFET, an LED and if you wish to extend the antenna, solder on a 1 meg resistor. I didn't have one on had the other day, but needed to get one out the door for a ghost-buster outfit, so I soldered on a 1k ohm resistor, worked as well as the 1 meg, in fact I think it was a bit more sensitive. These little units can detect a fellow combing his hair two rooms away on a dry day, The way I build them is quit simple on a 9 volt plug with the skin removed, solder the Gate to the + terminal, the source through the LED to the – terminal, the Drain works as the antenna and is where to attach the resistor to extend the range. To use, simply hook it up to a fresh 9 volt battery and keep an eye on the LED, it will pick up any negative voltage flux within a room or two. I have three of them that I built using different methods, the second one is built on the same basis but using a plastic enclosure and having the works hidden as well as a toggle switch to add to the professional look. I have a few other type I have put to gather, one based on an Arduino to read the voltage and light up LEDs depending on strength, from one LED to 10 for full force. Another I built following Big CLive's video but instead of using rabbit ears, which I could not find in our small town, insted I mounted her on a project board, then used a couple of pieces of heavy copper wire recovered from an old Power Supply These things are great fun!
Hello, Julian… I'm big fun of your videos, howether I'm complete amateur… What you showed us here amazed me. i know, I'm noob. But, I have one very important question for you. I'm sure it's possible, but I have no idea how to make it on breadboar, so… If you don't mind? Is this possible to boost transistor reaction, so it could "feel" my finger from, let's say 5cms away or 10cms? I will play for sure with yourdemonstration, but my idea is to use the transistor to react on eletro-magnetic field (let's say 5cm) and then digitally use it as a bit (I guess another transistor could help me to turn 5V on when transistors is "in range"). Yeah, I will be reading and trying… My idea is to have two or three such transistors generating digital answers and the difference in time (small changes in time (measuread by simple timer) – should allow me to use these transistors for "simpliest radar"… Simply – if I know which transistor is closest to magnetic field – I know where is the source of the field… Well, maybe my sci-fi idea, I'm complete amateur, but I'm working on something, right know it's a software simulation, but I want to build it in breadboard first and then… I hope to build something very simple and very amazin – I must say. Have a good day!
I am wanting to do this but want it more sensitive, so how would you connect say 2 or 3 of them together to make it more sensitive and I will be using 12 volt power supply from an old computer.
When I turned my jfet around (j111) it will stay on all the time…put it back the way it should be and it acts like yours with an off and on..
but why does a negative bias make the depletion regions grow (and vice versa)? my intuition says me it should be the other way around, because by putting more electrons into a P-region you should make it attract stray electrons from the N-region *less*, because now it's more negative which means there's less reason for the flow of negative electrons (depleting from the N-region) into it. therefore the depletion regions should shrink intuitively. why don't they?
So why is there a N and P channel fet…if you can exchange the Drain and Source??? very good video
But no led resistor?