Connected in series or parallel

In summary: In LED lighting applications, well-matched LEDs are often connected in series. But if one LED fails open, that opens the whole series string. Having the zeners in there in the forward direction let's the series current keep flowing in the forward direction, even if the LED fails open. That adds robustness to LED lighting applications.
  • #1
rineheart25
2
0
I am doing research on Zener diode and LEDs. I found a U.S. Patent #7518158.

http://www.google.com/patents?id=jlS_AAAAEBAJ&printsec=abstract&zoom=4#v=onepage&q&f=false

With respect to Fig. 4: Is the LED and Zener diode connected in parallel or series?
Thanks
 
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  • #2
rineheart25 said:
I am doing research on Zener diode and LEDs. I found a U.S. Patent #7518158.

http://www.google.com/patents?id=jlS_AAAAEBAJ&printsec=abstract&zoom=4#v=onepage&q&f=false

With respect to Fig. 4: Is the LED and Zener diode connected in parallel or series?
Thanks

It looks like the back-to-back zeners are connected in parallel with the LED. In the reverse direction they probably are for reverse breakdown protection. Do you know what function they would serve in the forward direction? I think I know (it may be in the patent also).
 
  • #3
berkeman said:
It looks like the back-to-back zeners are connected in parallel with the LED. In the reverse direction they probably are for reverse breakdown protection. Do you know what function they would serve in the forward direction? I think I know (it may be in the patent also).

I agree with you. It looks like the LED and back-to-back zener diodes are in parallel with the LED. They are connected in the reverse/antiparallel direction direction. In your question above, about the forward direction: I know of a two-way Zener diode that when connected in parallel with LED---the two-way Zener diode has two-way breakdown voltage and the diode can protect the LED from being damaged by electrostatic discharge (ESD). What are you getting at in the "forward direction"?
 
  • #4
rineheart25 said:
I agree with you. It looks like the LED and back-to-back zener diodes are in parallel with the LED. They are connected in the reverse/antiparallel direction direction. In your question above, about the forward direction: I know of a two-way Zener diode that when connected in parallel with LED---the two-way Zener diode has two-way breakdown voltage and the diode can protect the LED from being damaged by electrostatic discharge (ESD). What are you getting at in the "forward direction"?

In LED lighting applications, well-matched LEDs are often connected in series. But if one LED fails open, that opens the whole series string. Having the zeners in there in the forward direction let's the series current keep flowing in the forward direction, even if the LED fails open. That adds robustness to LED lighting applications. Neat idea.
 

1. What is the difference between connecting components in series and connecting them in parallel?

Connecting components in series means that they are connected one after another in a single loop, while connecting them in parallel means they are connected side by side in separate branches.

2. Which type of connection is better for increasing voltage?

Connecting components in series is better for increasing voltage, as the total voltage in a series circuit is the sum of the individual voltage drops across each component.

3. Can you mix series and parallel connections in a circuit?

Yes, it is possible to mix series and parallel connections in a circuit. This is known as a combination circuit.

4. How does the total resistance change in a series and parallel circuit?

In a series circuit, the total resistance is the sum of the individual resistances. In a parallel circuit, the total resistance is less than the smallest individual resistance.

5. Which type of connection is better for ensuring all components receive the same current?

Connecting components in parallel is better for ensuring all components receive the same current, as the current in a parallel circuit is split between the branches and each component receives the same amount of current.

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