OK, so I couldn't resist adding my 2 cents.
Most all ematches will fire in 1 millisecond. Especially when hit hard
with more current than their minimum all-fire current, which is what
happens when you connect a 9V battery to a 2 ohm load (4.5 amps vs. 0.5
amp typical all-fire). In this case they generally respond in less
than 1/2 millisecond. That's why we spec out a 1 ms current rating
for our timers, as well as longer duration current specs.
Other igniters like Aerotech FirstFire, Estes, etc clearly take longer
to respond, as they aren't made the same as sensitive e-matches.
That's why we list a different current spec for longer duration loads
like this kind of igniter.
With a beefy enough battery, the MT3G will fire 50 ematches in parallel
consistently and reliably. It will also fire 10+ FirstFire/QuickBurst
style igniters, and 20+ Estes igniters simultaneously. In fact if you
short the igniter terminals with a foot of 26 ga copper wire and use a
7.2V RC car NiCad pack, the wire "igniter" will disintegrate into
balls of molten slag on time-out without damaging or warming the timer
at all (no pyrogen, just copper wire!)
We also sell a high-current 9V NiCad that will fire 5 or more Estes
igniters in parallel with the MT3G, without the added volume and weight
of "doubling up" 9V alkalines.
Also bear in mind that some timers will reset and fail to fire if they
are overloaded and the battery voltage drops below a certain level. If
the battery voltage drops to an in-between value the FET can become
unsaturated, causing immense power dissipation and failure of the FET.
Our timers are not susceptible to either of these problems.
Setting the time delay with a simple button rather than a dipswitch
offers several advantages that I am aware of: A much less limited
range of time delays (0.6 second to over 6000 seconds in our case),
better resolution (0.1 second steps in our case), and you don't need
to refer to a manual to figure out how to set it. If you want 4
seconds, you hold the button down for four seconds. What could be
-- Peter Lawall