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[Stavros]

HELP me forgotten how to do it,someone out there please put me out of my miserey I have forgotten how to calculate a voltage drop by way of resistors

Stavros

[bigford]

hope this helps
http://led.linear1.org/1led.wiz

[boatmadman]

If i remember correctly, if you connect two 3v lamps in series with a 6v battery they will work ok as each lamp sees a voltage drop of 3v.

If coonected in parallel to the battery, each bulb will get 6v and pop.

Ian

[Stavros]

Thats what I was initially thinking BUT was not a 100% sure thats why me asked!!!!!!!!!!!!!!!!!!!!!Blown too many things up in the past

Stavros

[Colin Bishop]

Just don't connect the red wire to the black wire. 

[Stavros]

Oh Colin me definatly NOW have a problem cos both DAMMED wires are guess what     BLACK


STAVROS

[portside II]

good job it's not mains (240v) cos thats ,
green to green
brown to brown
blue to bits
daz

[OMK]

Stav, remember that incandescent lamps are not like LEDs -- lamps are not fussy about polarity. But in order to calculate the required voltage dropper resistor, you need to know the current (amperage) rating. Look on the metal casing of the lamp. It might say something like 30mA or 60ma or 80mA or....
If you can come back with the mA number, I'll show you how to calculate the value for the needed dropper resistor.

[Stavros]

Hi this is the problem I have nothing on the lamps,they are sealed will have to contact the supplier


Stavros

[Shipmate60]

Stav,
To run 3volt lamps off a 6 volt battery.
Get 2 lamps
Solder one wire from each lamp together
Treat both lamps as 1 6 volt lamp with the 2 remaining leads.
If 1 blows they will both go out.

Bob

[Stavros]

 


Stavros

[DickyD]

Just like the old christmas tree lights Stavros, 80 three volt lamps for 240 volts. Then one out all out.

[wombat]

Of course if you have four bulbs, connect the bulbs in pairs like Shipmate60, then connect the wires at one end of the pairs together, the wires at the other end together and  the wires in the middle together - then if one bulb fails, only that one will go out - the others will shift in brightness, but still glow - the more bulbs in the mesh the less effect one blowing has.

Wom

[Stavros]

Thanks for all your replies with my luck with blown thingies I just had to ask just to be on the safe side.I would have hated to have blown them up cos they look quite pretty on the  old fire boat!!!!!!!!!!!!!!!!


Stavros