Mad Scientists Light

Step 4:

Here is the insides of the box/base where you can see the back side of the light bulb sockets as well as the back end of the dimmer switch and all the interconnecting wires. the Sockets were wired in parallel (one linking to another like a daisy chain) with one end of the power cord connected to the daisy chain of sockets, and the other end of the power cord connected to the dimmer switch.

Comments

[anim8er]

Before getting to this page, I was going to suggest wiring the bulbs in series and do away with the dimmer altogether. As you found out, wiring the bulbs in series causes them to be dimmed. If that is how you want it, the dimmer is then unnecessary. (You would still want a regular switch.)

[garrys newman]

series wiring decreasse the voltage to each bulb (divided by 4 in this case) but also decreasse total consumption in AMPs (divided by 4 in this case)
so wiring in paralel have advantages: 4times more power to each bulb
and wiring in series also have advantages: 4times less power consumption thant series wiring

[brian3140]

"garry" its possible you have it right in your head, but what you wrote was a little confusing and sounded wrong so i just wana clarify for people referring to this instructable for learning purposes...

Volts x Amps = Watts
Wattage=Power Consumption

The power consumed by the lights will not change dramatically by wiring the lights in series or parallel. The lights "require" a specific wattage, eg. 60w, and besides adding a dimmer, will just "automatically" get it.

By wiring the lights in series, you increase the amount of resistance in the circuit, and this reduces the voltage like was pointed out already. But it does NOT reduce the amount of power you are using. If you refer the the formula I wrote above and keep in mind the Wattage is going to be constant, you can understand how when the voltage decreases the light will respond by increasing the amount of amperage. In fact this is how many house fires are caused because amperage causes heat. The old christmas lights without the fuses could get so hot they'd melts when you plugged to many strings into eachother like this.

The ONLY way to reuce the power consumption in a light circut like this is with a dimmer, and not all dimmers qualify. The modern Levitron dimmersw you pay about $20 a piece for DO reduce the power consumption, but the old style only reduce light output and not consumption.

Hope that was helpful :)

[garrys newman]

 if its writen 60w on a buld it will be 60watt on its nominal voltage ex:120v

let calc internal resistance of the bulb

R=U/I
U=120v
I=60/120=0.5

R=120/0.5=240 omhs

now let see if at 60volts it stay at 60w (60volts 1 amp)
I=U/R=60/240=0.25
0.25*60=15w

as you can see, according to ohm law, if voltage to buld decreasse, amp decreasse too

[anim8er]

Gary has it correct. In parallel, each bulb gets 120volts. Wired in series, for 4 bulbs, then each bulb only gets 30volts. The 120volts is divided across all 4 bulbs in series, but individually, they get a fraction of the total voltage drop.

The reverse is true. Standard batteries are 1.5 volts each. Wire them in series and the voltages add up. Lots of items use 3 batteries wired in series to produce 4.5volts. Close enough to power electronics meant for 5volts.

[PKM]

Yep, Garry is right. Wiring multiple bulbs in series not only decreases the power consumption per bulb, it actually reduces power consumption overall.  The entire string taken as a single "entity" has a higher resistance, so draws less current.

It's not quite as simple as four times as many bulbs = four times the resistance = one quarter of the current, because the resistance of a lightbulb depends on its temperature, so a lightbulb driven at half the voltage will draw more than half the current.  With longs strings of bulbs in series (like the old christmas lights), sometimes you can see them initially turn on brightly when the string is cold and at a low resistance, then dim as they heat up and increase resistance.  In this case, the effect would be quite mad-scientist-y anyway :)

[andybiker]

I second this,
Put the bulbs in series, 2 in series will run them at half the voltage. They WILL take less power. If the brightness of 2 bulbs in series is the same as using a dimmer then the power taken should be the same.
Forget Ohm's law with bulbs, the resistance (R) is not constant! A hot bulb has a higher resistance than a cold one!
Also make sure the bulbs are the same wattage or the power (and hence brightness) will be shared unevenly.

I wired 2 sets of old Christmas lights in series for my parents (about 10 years ago) - the brightness looks about 50% less (approx !) but the bulb life is MUCH longer!
I remember quite a few of these old (approx 60 years!) bulbs failed when I was a kid, but none of them have failed since!

[badideasrus]

im confused here. what brian said is true. voltage and amps have an inverse dependent relationship. (i hope i said that right) if one goes down, the other goes up. period. this is because watts are constant. this is why transformers work, if you decrease volts you get amps, if you decrease amps you get volts....... so if you wire them in series, the amps should go up because the resistence goes up. THIS is what causes the volts to go up, yes?

[andybiker]

No!
Bulbs are not transformers, completely different
When the resistance goes up then the current goes down!
I(current)=V(voltage)/R(resistance) (Ohm's law)
If you have a 100W bulb running on 110v, it will take 100 Watts ONLY when running on 110v.
If you run it on a lower voltage then it WILL take less current!
Try this simple experiment...Switch on the headlights of your car then start the engine. As the starter is turning then the lights dim (the voltage of the battery is dropping) then the engine starts and they are brighter (higher voltage-battery on charge!)
The brightness IS proportional to the actual watts being consumed by the bulb.
When we put 2 bulbs in series, the same voltage is shared between 2 bulbs. Twice the resistance*, Half the total power consumption, each bulb running at a quarter of the wattage*

*I mentioned earlier that a cold filament is a lower resistance than a hot one so this isn't exactly true but it gets complicated here!
I hope this helps!
Cheers,
Andrew

[mattimusmaximus]

(I know very little about electrical) Ive connected it in the same fashion as you've described here and i can only get a dim light out of the bulbs, it worked bright with only one (tested it when i started) is there a way to boost it, or is it the way ive set it up

[mattimusmaximus]

Never mind i switched the set up so that they were'nt in a series (daisy chain w/e) but were all brought back to the two source wires, looks fantastic so far

[Xilinx]

It's a fuzzy pic but the next photo clearly shows them wired in parallel. All the Hot(Black wires) tied together and all the Neutral(White wires) tied together.

I'm not saying_{, I'm just saying}

[coderj]

Sockets were wired in parallel (one linking to another like a daisy chain)
Actually, that's wiring them in series. Parallel is when all 4 share the same ungrounded coming off the dimmer, and the same grounded going to the dimmer.