# Open switches, current

1. Jan 6, 2012

### Mukilab

1. The problem statement, all variables and given/known data
There is a circuit with 7 LEDS connected in parallel, each with a switch on its parallel. There is a battery supplied.

The LEDS correspond to those of a digital clock for example the number 8 would light up all 7 LEDS, whilst the number 0 would light up 6 LEDS.

Which number from 0 to 9 draws the least current from the battery (For example to light up 3 I would have to close 5 switches)

2. Relevant equations

V=IR

3. The attempt at a solution

I'm slightly confused. Since the voltage is remaining the same, the only thing that would make the resistance decrease would be the resistance. I think (please correct me if I am wrong) that an open switch causes infinite resistance, therefore the number with the most open switches would cause the least current, number 1 as 5 LEDS are off

Any idea would be helpful, thanks

2. Jan 6, 2012

### Staff: Mentor

I agree that displaying 1 draws the least current.

3. Jan 6, 2012

### Mukilab

Thank you very much, question is answered, this thread is now obsolete.