Buy one of the excellent night lights available.
4 rechargable batteries in series would be the go.
Give up the booze David
On Wed, 3 Sep 2003 19:57:25 +1000, "Shane Kirkman"
shanekirkman@yahoo.com.au> wrote:
I want to make a night light for my young son, using a led.. Either plugin
240v or a couple of batteries and switch.Only newbie so I need a good
description or schematic.
Thanks Shane.
4 rechargable batteries in series would be the go.
Use say a 39ohm resistor in series with the white LED and switch. If
you want more than one LED then just duplicate the circuit (one
resistor for each LED). Could use multiple switches to turn on/off
multiple LEDs.
AA batteries should last for ages.
Regards
Dave
---------------------------
(remove the "_" from my email address to reply)
(4V8 - 3V6 (white LED I said, not RED)) / 39 = 31mA4 rechargable batteries in series would be the go.
Use say a 39ohm resistor in series with the white LED and switch. If
you want more than one LED then just duplicate the circuit (one
resistor for each LED). Could use multiple switches to turn on/off
multiple LEDs.
AA batteries should last for ages.
Give up the booze David
4 x 1V2 = 4V8
(4V8 - 1V8) / 39 = 77mA
I think David intended to type a 390R resistor
Mike Harding
Still works when the mains fails too - bonus.
Build the battery one first, you might need it before you progress on
Oh, fair enough, apologies, never used white LEDs andOn Wed, 03 Sep 2003 20:39:34 +1000, Mike Harding
mike_harding1@hotmail.com> wrote:
4 rechargable batteries in series would be the go.
Use say a 39ohm resistor in series with the white LED and switch. If
you want more than one LED then just duplicate the circuit (one
resistor for each LED). Could use multiple switches to turn on/off
multiple LEDs.
AA batteries should last for ages.
Give up the booze David
4 x 1V2 = 4V8
(4V8 - 1V8) / 39 = 77mA
I think David intended to type a 390R resistor
(4V8 - 3V6 (white LED I said, not RED)) / 39 = 31mA
You must get thirsty?
Assuming NiMH AA batteries:On Wed, 03 Sep 2003 20:39:34 +1000, Mike Harding
mike_harding1@hotmail.com> wrote:
4 rechargable batteries in series would be the go.
Use say a 39ohm resistor in series with the white LED and switch. If
you want more than one LED then just duplicate the circuit (one
resistor for each LED). Could use multiple switches to turn on/off
multiple LEDs.
AA batteries should last for ages.
Give up the booze David
4 x 1V2 = 4V8
(4V8 - 1V8) / 39 = 77mA
I think David intended to type a 390R resistor
Mike Harding
(4V8 - 3V6 (white LED I said, not RED)) / 39 = 31mA
I don't drink :-
Regards
Dave
---------------------------
(remove the "_" from my email address to reply)
So you charge the batteries once a week, no big deal.
So you charge the batteries once a week, no big deal.
There's a circuit in the latest Electronics World that has a white"David L. Jones" <tronnort_@yahoo.com> wrote in message
news:3f55c7e9.5996878@News.CIS.DFN.DE...
On Wed, 03 Sep 2003 20:39:34 +1000, Mike Harding
mike_harding1@hotmail.com> wrote:
4 rechargable batteries in series would be the go.
Use say a 39ohm resistor in series with the white LED and switch. If
you want more than one LED then just duplicate the circuit (one
resistor for each LED). Could use multiple switches to turn on/off
multiple LEDs.
AA batteries should last for ages.
Give up the booze David
4 x 1V2 = 4V8
(4V8 - 1V8) / 39 = 77mA
I think David intended to type a 390R resistor
Mike Harding
(4V8 - 3V6 (white LED I said, not RED)) / 39 = 31mA
I don't drink :-
Regards
Dave
---------------------------
(remove the "_" from my email address to reply)
Assuming NiMH AA batteries:
1800mAH / 31mA = 58 hours.
58 hours / 11 hours per night = 5 nights.
Not exactly "ages" ...
You could also PWM the led to reduce the current consumption, and varyOn Wed, 03 Sep 2003 14:21:57 GMT, "Defibrillator" <nospam@for.me
wrote:
Assuming NiMH AA batteries:
1800mAH / 31mA = 58 hours.
58 hours / 11 hours per night = 5 nights.
Not exactly "ages" ...
So you charge the batteries once a week, no big deal.
If that's a major gripe you can use D cells that would last in the
order of 258hours using your calculations.
Actually, 31mA might be too bright for a night light (single LED
lights are more than enough to bushwalk with or light up a tent at
night for example). 10mA or lower might just do the trick.
Dave
---------------------------
(remove the "_" from my email address to reply)
So what? The frequency can be adjusted such that the eye perceives it as a constant light.
So what? The frequency can be adjusted such that the eye perceives it as
Sure, but the OP is a newbie and wanted a simple solution, which is