6V to 3V without a regulator

Go to Goodwill, and select a 3VDC wall wart. They're $1 apiece.

Michael

SUrely 2 C cells will last a fair amount of time. It's the smaller AA and AAA that don't,, or for that matter the gadgets using button cells (which have the further disadvantage of being costly to replace). If life is really an issue, run it off two external D cells.

Or, put 4 or 5 silicon diodes in series, and with the cathodes facing towards ground. Then figure a dropping resistor to limit current. It will be sort of like a zener diode, and the about .7v voltage drop on the diodes will add up to 3V. Or just use the didoes in series between the adaptor and the display.

Michael

The

going

overkill.

For the future, when you *do* want a 3V regulator, here's a couple that are easy:

---- D1 D2 D3 +6 ---+---|7805|---+--->|--->|--->|--- Vout ~2.9V | ---- | [.33uf] | [.1uf] | | | Gnd --+------+-----+----------------- Gnd

For more precision:

----- +6 ---+---|LM317|---+------+------ Vout 3V | ----- | | | Adj [240R] | | | | | | +------+ | | | |+ [.1uF] \\ [1uF] | / 500 | | \\

Thanks

I don't know about overkill, but it's not hard to find them- Digi-key lists about 700, some between 50 cents and $1.50.

-- John

Why don't you just use a resistor dropper? This only works if the current drawn is sesibly constant. If you are driving the same number of LED's at all times then you could use this approach. Failing that then you could just use a high power zener diode, and a resistor. If all you're driving is LED's then this should be manageable.

You can 3.3v zener diodes quite easily, or you could use a chain of 5 rectifiers, such that 5 * 0.6 = 3.

Could it be easier?

Rob.