Steve Lawson

I just discovered the LT1932 which might work for the 1.5V case, and even for the 3V case.

Also, for the 6V to 12V array case, the LT1618 can be used in the constant voltage mode, as long as the current requirements of the 12V array don’t exceed it’s capability.

What you need is a switching constant current source (It’s better to drive LEDs with a current source rather than a voltage source).

For cases where the source voltage is 1.6V to 18V, there is the Linear LT1618 in constant current mode. The app notes on the Datasheet…

Sure:
1. A tiny thermalpile (just add heat)
2. Piezo electric (needs mechanical stimulous)
3. A tiny inductor that harvests power from ambient EMF
4. A tiny inductor next to a tiny magnet (agitate the inductor, the magnet or both)
5. Tiny vile containing acid with two tiny probes of dissimular…

And, for a variable output, try the attached. Set R4 to zero if you want it adjustable to zero volts, otherwise R4 will set a minimum voltage (thus making the adjustment more sensitive). Also, you might need to use two zeners in series to get a high enough voltage.

Forgot to mention, you might need a heatsink on Q1.

Why not just buy a transformer with the desired output voltage and then add linear power components such as a bridge rectifier and a regulator of some sort. Then all you will need is a square wave generator with a power output.

The thing about amplifying square waves is, it’s very easy. Just…

Mr. Seshardri’s comment about resistors that are rated at more than 1 watt is incorrect. Using a resistor rated more than a watt will not “fry the circuit”. In fact, the circuit will not behave any differently (aside from being a lot heavier ;)

The wattage rating on a resistor is merely how much…

Potential means the Potential to move charge. Also know as “Voltage”, Potential is like pressure in a fluid system. Potential difference is like a difference in pressure. Also, a difference in Voltage. In a circuit, there will be potential at one point [V1] and potential at another point [V2]….

These sound suspiciously like examination questions. Time to crack the books?

You could train a dog to bark when it smells smoke