# Series-Parallel Circuit

Joined Apr 10, 2006
5
I was wondering if someone could show me a way to build a Series-Parallel Circuit using light bulbs. I have four light bulbs, They are:
6.3V @ 150mA
6.3V @ 250mA
2.5V @ 500mA
2V @ 60mA
I have to use at least one of each bulb, but I can use more than one, if I want to. The applied voltage is 9V. The hard part about making this circuit is that it has to be somewhat power efficient. The bulbs should use at least around 60+% of the circuit. the smallest resistor I can use is a 2.7 Ω. I have come up with some circuits that will work but they are not very power efficient. The highest power efficiency I can come up with is about 45%. Anyone's help on this will be greatly appreciated.

#### paultwang

Joined Mar 8, 2006
80
Originally posted by MrBadVoodoo@Apr 10 2006, 01:49 AM
light bulbs.
6.3V @ 150mA
6.3V @ 250mA
2.5V @ 500mA
2V @ 60mA
[post=16026]Quoted post[/post]​
Do you mean Light Emitting Diodes?

#### windoze killa

Joined Feb 23, 2006
605
Originally posted by paultwang@Apr 10 2006, 08:47 PM
Do you mean Light Emitting Diodes?
[post=16029]Quoted post[/post]​
I certainly hope not, not with 500mA flowwing through one them. I am guessing he is using small liliput bulbs.

Joined Apr 10, 2006
5
Originally posted by windoze killa@Apr 10 2006, 04:35 PM
I certainly hope not, not with 500mA flowwing through one them. I am guessing he is using small liliput bulbs.
[post=16057]Quoted post[/post]​
CM 40 - 6.3V @ 150mA
CM 46 - 6.3V @ 250mA
CM 43 -2.5V @ 500mA
CM 49 - 2V @ 60mA

They are just small little bulbs that you might use in a car (lights for your dash board/ lights for your overhead light etc.)

#### paultwang

Joined Mar 8, 2006
80
Originally posted by MrBadVoodoo@Apr 10 2006, 08:50 PM
CM 40 - 6.3V @ 150mA
CM 46 - 6.3V @ 250mA
CM 43 -2.5V @ 500mA
CM 49 - 2V @ 60mA
[post=16065]Quoted post[/post]​
so they have fixed resistances at the given voltage level?

#### pebe

Joined Oct 11, 2004
626
Originally posted by MrBadVoodoo@Apr 10 2006, 07:49 AM
I was wondering if someone could show me a way to build a Series-Parallel Circuit using light bulbs. I have four light bulbs, They are:
6.3V @ 150mA
6.3V @ 250mA
2.5V @ 500mA
2V @ 60mA
I have to use at least one of each bulb, but I can use more than one, if I want to. The applied voltage is 9V. The hard part about making this circuit is that it has to be somewhat power efficient. The bulbs should use at least around 60+% of the circuit. the smallest resistor I can use is a 2.7 Ω. I have come up with some circuits that will work but they are not very power efficient. The highest power efficiency I can come up with is about 45%. Anyone's help on this will be greatly appreciated.
[post=16026]Quoted post[/post]​
I can get a max efficiency of about 46.5% by only using 1 of each bulb. But you say you can use more than 1 of each and you don't give a maximum or any current limitation.

So you could wire extra banks of 2v and 2.5 v bulbs in a series/parallel arrangement wiithout series resistors to get an overall efficiency approaching 100%

Joined Apr 10, 2006
5
Originally posted by pebe@Apr 11 2006, 09:59 AM
I can get a max efficiency of about 46.5% by only using 1 of each bulb. But you say you can use more than 1 of each and you don't give a maximum or any current limitation.

So you could wire extra banks of 2v and 2.5 v bulbs in a series/parallel arrangement wiithout series resistors to get an overall efficiency approaching 100%
[post=16089]Quoted post[/post]​
The current for this circuit is 1A ≤and I can use however many of each bulb I want. I at least have to use one of each bulb. Thanks for trying to help me.

Joined Apr 10, 2006
5
Originally posted by paultwang@Apr 10 2006, 10:32 PM
so they have fixed resistances at the given voltage level?
[post=16070]Quoted post[/post]​
They have no fixed resistances on them that I know of. The CM # is what it says on the bulbs themselves. I hope that answers your question. Thanks

#### pebe

Joined Oct 11, 2004
626
Originally posted by MrBadVoodoo@Apr 11 2006, 11:45 PM
The current for this circuit is 1A ≤and I can use however many of each bulb I want. I at least have to use one of each bulb. Thanks for trying to help me.
[post=16109]Quoted post[/post]​
You can get over 75% efficiency. As it's homework I won't give the answer, but I'll give you a hint.

Use one of each of the 6.3v bulbs, 2 of 2.5V and 8 of 2V bulbs.

Joined Apr 10, 2006
5
Originally posted by pebe@Apr 13 2006, 05:00 PM
You can get over 75% efficiency. As it's homework I won't give the answer, but I'll give you a hint.

Use one of each of the 6.3v bulbs, 2 of 2.5V and 8 of 2V bulbs.
[post=16155]Quoted post[/post]​
Thanks, I'll see what I can come up with.

#### pebe

Joined Oct 11, 2004
626
Originally posted by pebe@Apr 14 2006, 12:00 AM
You can get over 75% efficiency. As it's homework I won't give the answer, but I'll give you a hint.

Use one of each of the 6.3v bulbs, 2 of 2.5V and 8 of 2V bulbs.
[post=16155]Quoted post[/post]​
Correction. Use 16 of 2v.