1. We will be in Read Only mode (no new threads, replies, registration) starting at 9:00 EDT for a number of hours as we migrate the forums to upgraded software.

Simple Diode Circuit Help

Discussion in 'Homework Help' started by fiz, Oct 16, 2006.

1. fiz Thread Starter New Member

Oct 16, 2006
2
0
I am having a hard time grasping how to simplify circuits with diodes (assuming a piecewise linear model w/ a turn on voltage of 0.7 V). I have attached a picture of a circuit with a 2 diodes in series and 3 other resistors in the circuit. I am having trouble trying to figure out where to start to calculate I1. I want to add resistors to simplify but none are in series or parallel. Any help would be appreciated. Edit: Sorry it's hard to read, R1 and R3 have values of 1k Ohms and R2 is 500 Ohms.

2. beenthere Retired Moderator

Apr 20, 2004
15,808
295
Hi,

It's a pretty simple series-parallel circuit. The two diodes drop 1.4 volts off the voltage that would normally be across R2. Otherwise, it's just a series resistance and two parallel branches.

3. fiz Thread Starter New Member

Oct 16, 2006
2
0
Ah, thanks. To make sure just simplify the circuit as if the diodes aren't in it, as in add R1 and R2 and then take that value and add it to R3 (1/R1+R2 + 1/R3)^-1 then use that resistance value to get I1? If my thinking is right I can figure out the rest.