I connected 4 x 1000Ω resistors in parallel. Left side is 5V and right side is ground.
1 1 1 1 1
- = - + - + - + -
R(total) R1 R2 R3 R4
1 1 1 1 1
- = - + - + - + -
R(total) 1k 1k 1k 1k
1 4
- = -
R(total) 1k
1 1
- = -
R(total) 250
R(total) = 250Ω
Just the four resistors in parallel are 250Ω
1 1 1 ---- = ----- + ----- 231 Runo 250
1 250 + Runo
--- = --------------
231 250 * Runo
250 * Runo = 231 ( 250 + Runo )
57750 = (250 – 231) Runo
57750
----------- = Runo = 3.039kΩ
19