Hobbyist Forums banner

1 - 4 of 4 Posts

·
Registered
Joined
·
270 Posts
Discussion Starter #1
I can't count the many times I've heard modelers talk of connecting strips in series vs parallel. Apparently few know the difference between the two.

What is described as connecting in Parallel is merely connecting each strip to its own power leads instead of connecting the end of the strip to the next. Connecting one strip directly to the next is NOT a Serial connection. It may be more appropriate to call it cascading strips.

It can be viewed the same as connecting individual LED's. You can connect each LED to the power source and these would all be in parallel. You can also connect each LED in series where Neg is connected to the first LED, the Pos of the first LED is connected to the Neg of the second LED and the Pos of the second LED is connected to the Neg of a third LED and the Pos of the third LED is connected to the Pos power source. THIS is a series circuit. If the total number of LED's and their voltage drops are sufficient there need not be any resistors added.

By the same token if you were to series add LED strips the Pos of one strip would need to be connected to the Neg of the next, as above. The reason this isn't done is because each LED in the strip already has its resistor on board.

I only mention this because it is misleading and confusing if one wants to understand circuits and apply it to their own projects. A person may try to use series or parallel where it doesn't apply and cause damage.

Greg
 

·
Registered
Joined
·
2,241 Posts
Hi Greg, just realized you answered this. I hadn't read your post beyond the first line, sorry. You are right, though.

Adding my two cents (not adjusted for inflation):

Think of it this way. Connecting in series is like a long train, each car connects to the other in a straight line. Connecting in parallel is like having different trains next to each other.

In series, the power wires connect to the one strip of lights, light connected to the next - they all use the same amps, but the voltage drops from one end of the strip to the other. Say each light uses 1.5v in an additive fashion, then if you have a string of 4 lights in a row, they will use 6v total. So, your power has to be say 500 milliamps at 6 volts output.

In parallel, you have a set of power wires going to each of the individual strips that are next to each other. Here, volts stay the same and amps go down. So, pulling the figures out of a hat, check your leds to find out their voltage and amperage ratings, each led has 50 milliamps and 1.5 volts each, and you have 10 leds next to each other. Well, the volt output of the power supply is only 1.5 volts. But, the total amps add up here, so 50 milliamps x 10 leds = 500 milliamps. So power supply would have to put out 500ma (short for milliamps) and 1.5v (short for volts).

It can get more complex when you parallel strips of lights that are in series!

Hope this helps!
 

·
Registered
Joined
·
270 Posts
Discussion Starter #3
Lest anyone gets confused, in LED strips each LED is in parallel to the power wires. That is why you can cut sections for different areas and wire one end to the next strip with no change in LED output.

I think you are referring to individual LEDs arranged serial or parallel.
 

·
Registered
Joined
·
2,241 Posts
Yes, individual leds or grain of wheat lamps. I should have been more clear on that.
 
1 - 4 of 4 Posts
Top