Simple Square wave oscillator?

[Firnagzen]

Could someone reccomend a really simple square wave generator that'll work down to about 1.9v? Or will I have to rely on the good ol' astable multivibrator?

Also, could someone reccomend me a common NPN transistor capable of standing up to 1A with the lowest possible Vce(sat)?

 

[mneary]

Or will I have to rely on the good ol' astable multivibrator?

Please describe your problem.....

 

[Firnagzen]

Sorry, I forgot to mention, and was just about to when I called up this topic and you had already replied.

Alright, I need something to replace the Schmitt inverter based oscillator in this circuit: **broken link removed**

That, I think, should be sufficient, right?

Thanks.

 

[ericgibbs]

Sorry, I forgot to mention, and was just about to when I called up this topic and you had already replied.

Alright, I need something to replace the Schmitt inverter based oscillator in this circuit: **broken link removed**

That, I think, should be sufficient, right?

Thanks.

hi,
If you want to drive an LED with a 'semi-flat' 1.5Vbty, Google for: 'Joule Thief'

 

[Hero999]

How about using a switching regulator to convert your 1.9V supply to a more sensible voltage?

 

[Hero999]

As for low saturation voltage transistors, try any of the following:
ZXTN19020CFF
ZXTN25020CFH
ZTX869

 

[Firnagzen]

Because I want to keep the complexity down! Anyway, I think I've found a solution, thanks anyway...

 

[Hero999]

Care to post the solution?

I would use a 74HC00 to make an astable mult-vibrator, the IC is guaranteed to work at 2V but most will probably work down to 1.9V.