Thanks blue_leaf. Yes, I have nice controlled square pulses. I was given some numbers to beat by a Xenon strobe, but the numbers seemed off. Good to know.
I need to convert light energy: 138W/m2 to uJoules / mm2, at a 4usec pulse
J = W * seconds
J = 138 W/m2 * 4e-6
= 5.54e-4 J/m2 5.54e-4 J/m2 = 5.54e-4 uJ/mm2
answer:
5.54e-4 uJ/mm2Does this look correct?
I think a zener diode would work out just about right. You'll want to calculate the power so you size the zener properly, but I doubt the lamp draws that high of a current.
There is probably some resistance limiting current to the lamp, so a smaller zener would probably work ok. You can also...
You'll want to check the LED datasheet for typical operating voltage @ specified current.
Assuming a standard 5mm LED: White @ 20mA
(Vin - Vf) / R = I
Vin = 5 V
Vf = 3.2V (found from LED datasheet @ 20mA)
I = 0.02A
5V - 3.2 / R = 0.02A
R = 90 Ohm
Dont burn up your resistor! Calculate...
You can use "press and peel blue" and ferric chloride to etch your PCB design on a copper board. This is probably the simplest approach to a PCB prototype.
You essentially print your circuit with a laser-jet printer onto the blue film, iron onto a copper board, peel off the blue, and etch...
I am trying to measure very high light pulses by using photodiodes. Light levels are expected to be upwards of 2-3W of irradiance.
Pulse-widths are from 20uSec to 1mSec. Example light source is a highly over-driven high brightness LED, typically 200-300mW in power (during recommended current...