My Goal is to build this http://semiconductormuseum.com/PhotoGallery/PhotoGallery_Shockley4E30_Page4_files/image004.jpg

I usually buy from Mouser but they only have the other Schottky diodes for fast switching. I need shockley diodes but I don't know where to get them at? Do they even make them or do I have to use NPN and PNP transistors? I'm fairly new to all this stuff and this is my first post so any input is welcomed, Thanks

 

You could perhasp use a DIAC. If you use DC it should not matter much
http://www.allaboutcircuits.com/vol_3/chpt_7/4.html

 

You could perhasp use a DIAC. If you use DC it should not matter much
http://www.allaboutcircuits.com/vol_3/chpt_7/4.html

I've tried looking at the DIAC's here but the lowest breakover voltage is 32V. I need something closer to 3V for breakover voltage. Do these even exist?

I was thinking that i could make my own? Maybe get two diodes and make them into a 4 layer diode by connected one lead of each to the other?

 

No. Semiconductor devices don't work like that. For the same reason you cannot make a bipolar junction transistor by connecting two diodes together.

 

Maybe I'm over thinking the whole thing. I could be wrong but I think I could use regular didoes? A normal diode needs a forward voltage of 0.7V before it can conduct right? So If i put 7 in series the series of diodes would need 4.9 volts to conduct right? Charge a capacitor from high resistance resistor that's connected to a 9 volt battery. Once the capacitor voltage goes above 4.9V the diodes would conduct and discharge the capacitor? Sorry if i'm completely wrong.

Here is a diagram of what i'm trying to say https://docs.google.com/drawings/d/1cer4FLtmnJf97PR1RZ4e2YwltqOasCnku6yC6zysiuI/edit

 

why don't you use a Zener diode?

 

A bunch of diodes in series or a zener diode simply clamps the capacitor voltage at one voltage.

A Shockley diode (small signal ones are no longer made) breaks down and shorts the capacitor voltage to ground then opens, allowing the circuit to oscillate in a sawtooth waveform.

Many years ago I used a PUT (programmable unijunction transistor) to do the same thing. Look at it in Google or see the datasheet for a 2N6027.
You can also use two transistors if you want.
Today, Digikey has more than 100,000 2N6027 PUTs in stock for $.44 each.

 

Ordnary diodes donot switch, need something like tunnel diode, unijunction, programable unijunction, etc. Example: PUT 2N6028 with example ckt in thumbnail. Period is close to R*C. For a sawtooth, output is from top of cap. into a high Z .

 

A bunch of diodes in series or a zener diode simply clamps the capacitor voltage at one voltage.

A Shockley diode (small signal ones are no longer made) breaks down and shorts the capacitor voltage to ground then opens, allowing the circuit to oscillate in a sawtooth waveform.

Many years ago I used a PUT (programmable unijunction transistor) to do the same thing. Look at it in Google or see the datasheet for a 2N6027.
You can also use two transistors if you want.
Today, Digikey has more than 100,000 2N6027 PUTs in stock for $.44 each.

Thank you this is what i've been looking for. I've found a YouTube video that Explains how it works too. http://www.youtube.com/watch?v=pSFXuFs7kSA

I wonder why they stopped making Shockley diode's?

 

Ordnary diodes donot switch, need something like tunnel diode, unijunction, programable unijunction, etc. Example: PUT 2N6028 with example ckt in thumbnail. Period is close to R*C. For a sawtooth, output is from top of cap. into a high Z .

Thank you for the circuit, this is the type of circuit i was looking for.