Comments on: Avalanche pulse generator circuit

By: Tomi Engdahl

Tomi Engdahl — Fri, 27 Jun 2025 19:38:02 +0000

Does this work? The circuit idea is right, but usually somewhat more than 9V voltage is needed for that usually 12-18V.

How this bc547 LED flasher work with no Base biasing? : r/AskElectronics https://share.google/4Be9vW6NYHqcp69Hy

By: Tomi Engdahl

Tomi Engdahl — Thu, 05 Sep 2024 04:03:47 +0000

50ps rise time using an ultra fast SiGe comparator http://www.starlino.com/build-a-really-fast-pulse-generator-50ps-rise-time-using-an-ultra-fast-sige-comparator.html

By: Tomi Engdahl

Tomi Engdahl — Thu, 05 Sep 2024 04:02:18 +0000

Sean Breheny 2N2369 , BFG541 are good candidates. the SGS thomson 2N2369 work really well (gold pins) . the onsemi were slower (larger die inside) . keep in mind that none of these transistors are really designed for this. They will eventually die. There are special avalanche transistors like the FMMT413 or ZTX415 / FMMT415 . True avalanche transistors need a controlled pulse on their base to “fire” you can’t simply put a high voltage on them. An avalanche transistor has a negative resistance (called secondary breakdown) in the breakdown curve. You need to tune the collector voltage so that you stay just below the avalanche threshold. if then fire the base the transistor will avalanche. They need about 220 volt collector voltage. below that they just switch fast but do not enter avalanche operation.

Source https://www.facebook.com/share/p/fcdq61trfsryz9x4/

By: Tomi Engdahl

Tomi Engdahl — Wed, 20 Dec 2023 15:06:14 +0000

https://electronicprojectsforfun.wordpress.com/pulse-generators/avalanche-transistor-pulsers/

By: Tomi Engdahl

Tomi Engdahl — Wed, 20 Dec 2023 15:05:36 +0000

https://www.researchgate.net/figure/Complete-avalanche-pulse-generator-circuit_fig1_251842621

By: Tomi Engdahl

Tomi Engdahl — Wed, 20 Dec 2023 15:05:21 +0000

http://www.kerrywong.com/2013/05/18/avalanche-pulse-generator-build-using-2n3904/

By: Tomi Engdahl

Tomi Engdahl — Sat, 12 Oct 2019 11:55:20 +0000

Testing The Speed-of-Light Conspiracy
https://hackaday.com/2016/09/29/testing-the-speed-of-light-conspiracy/
http://www.jensign.com/sol/index.html

By: Tomi Engdahl

Tomi Engdahl — Wed, 30 Jan 2019 10:23:36 +0000

Example of low voltage avalanche circuit:

Transistor Avalanche Disaster
https://www.youtube.com/watch?v=DCc1zxuAsmw

30 or 40 transistors die in reverse biased avalanche breakdown catastrophe. You told me not to put components into a live circuit, and on this occasion, you were right. Also, some clever 1-transistor oscillators

By: Tomi Engdahl

Tomi Engdahl — Fri, 24 Aug 2018 07:55:48 +0000

Time Domain Reflectomety
https://www.youtube.com/watch?v=sqTR7FMaD68

Covers how to perform the function of a TDR by using an oscilloscope
and a pulse generator. Understanding the material in this video will
help you to understand how an actual TDR works.

By: Tomi Engdahl

Tomi Engdahl — Thu, 23 Aug 2018 08:47:54 +0000

“TDR” or Time Domain Reflectometer, build and use this circuit.
https://www.youtube.com/watch?v=I1gfUNh5PJQ

This is a simple avalanche type, TDR ( Time domain reflectometer ) which allows you to analyze many different issues with coaxial cable. This is the first video in a small series. I will also cover DTF, or “Distance To Fault,” how to determine Impedance, using this TDR to check an oscilloscope graticule, looking for hidden barrel connectors, or “a splice,” and so on….