pop-quiz *NEW PROBLEM!*

[star882]

What can be used to boost 1.5v to 3.6v for a LED, has 1 component, and is not an IC or module?

 

[MicroE]

A 2.1 Volt battery.
1.5 + 2.1 =3.6
---Marc

 

[star882]

Good guess but not right.
And before anyone says transformer, the input is DC.

 

[Monsters_Inc]

A magical device - like the magical animal that gives us ham, bacon and pork....

 

[txwest]

I guess I'ld buy one of these.... TX
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=1392390713
(and get rid of the 1.5V battery)

 

[Darell]

I give. But I DO like Tex's solution. The perfect single LED battery!

 

[Jonathan]

Originally posted by star882:
What can be used to boost 1.5v to 3.6v for a LED, has 1 component, and is not an IC or module?

<font size="2" face="Verdana, Arial">1) A small DC motor with appropriate taps on the commutator.

2) A solar cell.

3) A _variable_ capacitor. Set it to maximum capacitance. Charge to 1.5V. Disconnect the battery, connect the LED, and then adjust the capacitance down. Since the same charge is stored with reduced capacitance, the voltage has to go up.

4) A -100 ohm resistor (presuming that you want about 20mA)
-Jon

 

[star882]

"A small DC motor with appropriate taps on the commutator."
It works but it is not the answer I had in mind.
"A solar cell"
It cannot be a cell of any kind.
"A _variable_ capacitor. Set it to maximum capacitance. Charge to 1.5V. Disconnect the battery, connect the LED, and then adjust the capacitance down. Since the same charge is stored with reduced capacitance, the voltage has to go up."
Changing connections counts as a switch.
Thus, this has 2 components.

 

[MicroE]

Jonathan---I'm still looking for that single component -100 ohm resistor.
Can't seem to find it in the Digikey or Newark Electronics catalogs........
---Marc

 

[Jonathan]

Originally posted by star882:
"A _variable_ capacitor. Set it to maximum capacitance. Charge to 1.5V. Disconnect the battery, connect the LED, and then adjust the capacitance down. Since the same charge is stored with reduced capacitance, the voltage has to go up."
Changing connections counts as a switch.
Thus, this has 2 components.

<font size="2" face="Verdana, Arial">True, however I made an assumption: that there was a 1.5V supply; your original question said nothing about a 1.5V supply, just that there was 1.5V that needed to be boosted up to 3.6V to run the LED.
Thus I claim that my single component is an extremely large variable capacitor, set for maximum capacitance, which starts out charged at a potential of 1.5V, and is connected to an LED. When the capacitance is decreased, the voltage goes up, and the LED lights. *grin*

Anyhow, you've been keeping us dummies in suspense for long enough. Ya gonna dish already????

-Jon

 

[Jonathan]

Oh, and on your transformer comment: unless you are using the mystical ideal LED of which all man made LEDs are dim copies, as well as an eternal voltage source, I claim that you are _not_ supplying the LED with DC voltage. You have to turn the device on at some point, and the battery will eventually discharge.

Therefore, a _large enough_ transformer _will_ work. With a large enough transformer, when you connect the 1.5V, current will start flowing, ramping up with time because of the inductance of the primary winding. Because of the changing current, you will have a changing magnetic field, and because of the changing magnetic field, you will produce a voltage in the secondary. With an appropriate turns ratio, you will get the 3.6V in the secondary.

Eventually something will saturate and the current will stop increasing, and the output voltage will fall to zero. But for a large enough transformer, this could be a rather long time.

-Jon

 

[aso]

Are you talking about the doohickey mentioned here:

http://www.candlepowerforums.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=3;t=001762#000001

 

[star882]

Aso, you got it!!

 

[star882]

Now try using a 2n2222 transistor, a resistor, and a capacitor to make a LED flasher.
You can only use a bunch of 9v batteries in series to power the circuit.

 

[star882]

*bump*
How do you make this thread sticky?
Also, the circuit works for real but doesn't work on a simulation.