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very low voltage multivibrator

very low voltage multivibrator

very low voltage multivibrator

(OP)
I need a multivibrator circuit to drive two alternating(1hz) loads of 800ma using a 1.5 AAA cell. It needs to fit in a space about two inches by 1/2 inch and be as low as possible(1/4" to 3/8" max).  Preferably I would like to use all surface mount components.  I've been working with a Zetez zsct1555 timer but can't seem to get it to trigger once the capacitor charges.  It is the basic 555 timing circuit with Ra=220, Rb=3200, and Ct=100uf.  I have the timing circuit driving output circuitry, but have disconnected it for testing. I am testing it with a variable power supply.  Maybe my Ct leakage is too high?  How do I tell?  Maybe a two transistor multivibrator would be better, but I can't seem to find one that will opperate with my specifications for a reasonable cost.  Any help would be greatly appreciated!  Thanks!

FYI
I am building a swimming fishing lure using this circuit and may need volunteer product testers if you are interested.

RE: very low voltage multivibrator

NS Semiconductors make an LED Flasher Chip (LM3909 from memory) and it will run off 1.5V and deliver surprisingly high peak load curreents.  As for delivering 800mA loads from a AAA cell, that's asking a lot of the cell, even for short pulses.  Battery life will be short as AAA nicads (which are the best for high currents), generally have a capacity of only 180mAH.

RE: very low voltage multivibrator

(OP)
Thanks for responding to my post.  I will try to keep my current as low as possible, I might only need 400mA which the AAA should be able to produce for an hour according to Energizer and Duracell's web sites. I have looked into the 3909 from National and it is discontinued. Also I can't seem to even find it in surface mount,if they ever even made it.  I would like to use something still in production. I think the tsc1555 would be my best bet but I don't have any experience with this chip.  I have the data sheets, but they don't seem to be providing the answers I need.

RE: very low voltage multivibrator

(OP)
All readers,

Please also see "low voltage 555 Zetex zsct1555"

Thanks

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