# familiar with IGBT? how to use it in a strobe flash circuit?

#### rwmoekoe

Joined Mar 1, 2007
172
Hi everyone

A common strobe flash circuit with brightess preset until now usually is using a fast thyristor (such as cr3jm) as the 'quenched' switch.
You may refer to the circuit here:

<------ (edited) the link doesn't work! please refer to the attachment below in latter post

This is a schematic of a strobe flash with brightness / intensity preset.
I'm only gonna describe the presetting concept roughly, hope it's ok with you all.

The circuit part below the main circuit will act as (presettable) timer to cease the flash from firing. Yes, the level intensity is actually determined by the period in which the flash should fire.
The main switch that make this stopping possible, is the CR3JM fast thyristor. Normally, a common thyristor would fail to disengage. That's why a fast one is used instead.

The situation is like this:

#### hgmjr

Joined Jan 28, 2005
9,029
I too was unable to open the jpg file.

hgmjr

#### rwmoekoe

Joined Mar 1, 2007
172
The image shack link doesn't work.

Do I understand correctly, are you looking for less-than-$0.02 per IGBT in quantities of a few hundred? Such is likely unachievalbe. If price is your only reason for using an IGBT, then stick with the thyrsitor. thx thingmaker3 for responding the thyristor cr3jm, it's$6.00 per piece and sold for bulk 300 pcs. i am still bargaining and the latest quote was \$5.75 a piece sold for bulk of 100 pcs.

as a matter of fact, price is one reason, another is i'm afraid that the thyristor will be dicontinued of production, because some people say that it's obsolete already.

oh and i'm attaching the pic here. thx alot!

friendly,
robert

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#### thingmaker3

Joined May 16, 2005
5,073
Not 300 for 6, but 300 at 6 each! I understand now. If it were me, I'd go through the catalogs looking for the least expensive MOSFET or IGBT that will handle 120% or more of the voltage & current.

#### rwmoekoe

Joined Mar 1, 2007
172
Not 300 for 6, but 300 at 6 each! I understand now. If it were me, I'd go through the catalogs looking for the least expensive MOSFET or IGBT that will handle 120% or more of the voltage & current.
really? if you think so, my friend, i'll do just that.
can you help me with the schematic? i don't have any idea on using mosfet yet. in fact, the only mosfet i'm familiar with is the irfz44 and the series. only 40 volt max isn't it?

thx thingmaker3,
robert

#### thingmaker3

Joined May 16, 2005
5,073