How to measure trigger voltage of studio strobes

Sigma 18-200mm f/3.5-6.3 DC OS for Canon

04/03/2006 03:35:25 PM · #1

After reading about how high trigger voltage destroys digital camera, I too decided to probe trigger voltage of my strobes that run on electricty ,but i have no electronic knowledge.

After reading bit on net , it seemed so easy .

I am in India, we have AC current here but my american who is an expert in electronics told me trigger voltage as recived in Pc chord of my studio strobes is DC.

Well i am confused

ElGordo

Canon EOS-400D Rebel XTi

04/03/2006 03:49:28 PM · #2

The line power (AC) is converted to DC inside the strobe electronics for the flashtube. A portion of the flash tube voltage is divided down to a somewhat lower voltage, usually under 200 volts, and used to trigger the flashtube through a 'trigger transformer'. If you need specific details on strobe trigger circuits, search Google for more indepth info.

04/03/2006 03:53:56 PM · #3

SO it is DC and also I should use the option of DCV. How can I know the impendence of my multimeter, some wrote in of the forums Impendence of mutimeter also effects measuring of voltage

Prof_Fate

04/03/2006 03:56:19 PM · #4

Do you have a multimeter?
like this?

you set the dieal DC VOlts, put the two leads on the flash trigger wire contacts (with the flash ready to fire) and read the voltage. test fire the flash a few times and read the voltage.

then check with your camera manufacturer to see what is a safe voltage for your camera.

CarpeNoctem

Canon EOS-20D

Canon EF 50mm f/1.8 II

04/03/2006 04:05:08 PM · #5

Originally posted by Prof_Fate:

This may give you a false reading - erroring to the low side. The voltage is there then it's gone in a 'flash'. Unless the MM can be set to display the trigger voltage - you may be risking damaging equipment.

I would take it to an electronics store (not Radio Shack) but a home grown shop, ask them to measure the trigger voltages with an O-Scope. These scopes, running from $1000 on up, have settings to watch for trigger voltages and will display the value until cleared. Plus, the O-Scope can be set to a high enough frequency as to ensure you are view the whole pulse, an MM is hit or miss in determining what part or all of the pulse it measures.

-Rick

Canon EF 24-70mm f/2.8L USM

04/03/2006 04:17:57 PM · #6

My Multimter is like this

here are details about multimeter

DC VOltage Range : 600v/200v/20v/2v/200mv
AC Voltage Range : 600V/200V
Dc Current: 10 A/200ma/20ma/2ma/200ua
AC Voltage: 600v/200v

So is my multimeter all right. Also as per the photographraph DC Voltas is towards left side of the know right?
I have no clue abt electronics and no one to help me

leaf

Canon EOS-5D Mark II

04/03/2006 04:47:42 PM · #7

where do you find that tech info?.. shouldn't the sync voltage be stated on the flash info page?

here is a flash link for example..

this flash

04/03/2006 04:56:23 PM · #8

It is not given in my flash,

Sigma 18-200mm f/3.5-6.3 DC OS for Canon

04/03/2006 05:00:41 PM · #9

From what i have figured out , my Prolinchrom 23 has a trigger voltage of 10 v( at least thats what i could understand). My camera can take upto 500v.

ElGordo

Canon EOS-400D Rebel XTi

04/03/2006 05:05:25 PM · #10

Originally posted by General:

Your meter has an input impedance of 1 megohm. That will load the trigger voltage divider (on older units) and give a lower reading than the unloaded circuit voltage. Someone mentioned using an o'scope to measure the trigger voltage, same problem, a 1 megohm impedance; the voltage on the trigger pins is a steady DC voltage and no pulse is generated until the pins are shorted, thereby dumping the trigger charge capacitor into the primary of the trigger transformer (on older strobe units). The output of the trigger transformer is typically several kilovolts and is applied to the trigger electrode near the center of the flash tube.
Modern strobe circuits use a much lower initiation voltage at the trigger pins, some as low as 5 volts, that will turn on a mosfet that dumps a much higher trigger voltage into the trigger transformer. The bottom line: you can use your meter to measure the trigger pin voltage. If it reads more than 50 volts or so then it probably is the older type and actual voltage (unloaded) may be as high as 200 volts. If the reading is a more modest 4 volts to 12 volts then it a newer unit and is safe for most cameras. Good luck with it!

Canon EF 24-70mm f/2.8L USM

04/04/2006 12:21:23 AM · #11

Thanks for such a detailed reply. My strobe is a new strobe.

leaf

Canon EOS-5D Mark II

04/04/2006 03:02:04 AM · #12

i am thinking of buying some hensel strobes. I have heard their trigger voltage is 20volts. I have a canon 10D, which I think likes 6volts... I suppose this might be a problem? perhaps a radio sync would be a better option... or am i misunderstanding things.

kiwinick

Sony DSLR-A550

Sony DT 18-70mm f/3.5-5.6 Aspherical ED Zoom Lens for Sony Alpha

04/04/2006 03:07:22 AM · #13

easiest way to trigger these is to use a on camera flash with the compensation -2stops,
failing that a Wein or similar system is great

leaf

Canon EOS-5D Mark II

Canon EF 24-70mm f/2.8L USM

04/04/2006 03:34:30 AM · #14

ahh i found it.. i believe the sync voltage is 3volts

this page has it

This page which is with a radio reciever built in does not have it specified