Użytkownik "Andgro" <b...@a...com> napisał w wiadomości
news:4c484ffd$0$2585$65785112@news.neostrada.pl...

> Nie wierzę że da się włączyć zwykłą diodę LED na czas 2-3ns :)
> Zmierz pojemność kryształu w stanie przewodzenia i indukcyjność
> doprowadzeń. Przypuszczam ze BYĆ MOŻE realne są czasy o rząd dłuższe
> dopiero.


Jeszcze nic nie mierzyłem, ale zacytuje Ci kilka artykułów:

MHz LED source for nanosecond fluorescence sensing

http://iopscience.iop.org/0957-0233/13/1/311

"Optical pulses were recorded using the time-correlated singlephoton
counting technique [8]. A Phillips PM2257B photomultiplier tube [22] was
used to detect the optical pulses and the resultant signal was relayed to
the 'start' channel of a EG&G Model 567 time-to-amplitude converter (TAC)
via a constant fraction discriminator EG&G Model 584. The 'stop' signal for
the TAC was taken directly from the oscillator of the pulsed LED. Such
'reverse start-stop mode' of operation minimizes the TAC dead time [8]. The
output of the TAC was then fed to a Viking Model 5000 multichannel. analyser
for data acquisition. The blue-green (525 nm), green (560 nm) and amber (590
nm) LEDs were obtained from RS components (Catalogue Nos 228 1863, 585 395
and 826 723 respectively) and because of timing spread due to the
photomultiplier and NIM electronics the measured LED optical pulse FWHM
presented here are slightly broadened (approximately in quadrature) by the
instrumental impulse response FWHM which is 350 ps. Figure 4 shows the
spectral outputs of the three LEDs studied here recorded on a SPEX Fluoromax
fluorimeter. Figure 5 shows the corresponding pulse profiles. The FWHM were
1.9, 3 and 3.6 ns for the LEDs with peak emissions 525, 560 and 590 nm
respectively."




A CMOS Time-Resolved Fluorescence Lifetime Analysis Micro-System

http://www.mdpi.com/1424-8220/9/11/9255/
Dostępny za free

In 1995, Araki and Misawa [24] demonstrated the use of commercially
available blue InGaN/AlGaN LEDs for fluorescence lifetime measurements.
Driven by an external RLC (resistor, inductor, capacitor) circuit and
controlled by an avalanche transistor, these devices generated 4ns wide
optical pulses with a 10 kHz repetition rate and a peak optical power of
40mW. In order to operate the avalanche transistor required a 300 V
collector voltage.





Jest tego trochę więcej nie do wszystkich mam dostęp, zwłaszcza tych z IEEE
ale ogólnie to da sie wysterować diodę impulsami tego rzędu. Ja i tak nie
potrzebuję tak krótkich impulsów, mi wystarczy 10ns, ale te 10 ns to i tak
nie jest to tyle co Ty piszesz.

Pozdrawiam

JG