initial commit, voltage divider

voltage_divider.py

@@ -0,0 +1,37 @@
+#!/bin/python
+def find_bests(desired_ratio, resistors):
+    # only keep the 5 best candidates
+    candidates = []
+
+    for R1 in resistors:
+        for R2 in resistors:
+            ratio = R2 / (R1 + R2)
+            error = abs(ratio - desired_ratio)
+            entry = (error, R1, R2, ratio)
+            if len(candidates) < 5:
+                candidates.append(entry)
+                candidates.sort(key=lambda x: x[0])
+            else:
+                if error < candidates[-1][0]:
+                    candidates[-1] = entry
+                    candidates.sort(key=lambda x: x[0])
+
+    print("Top 5 resistor pairs closest to desired ratio:\n")
+    for i, (error, R1, R2, ratio) in enumerate(candidates, start=1):
+        print(f"{i}. R1 = {R1} Ω, R2 = {R2} Ω  -> ratio = {ratio:.6f}, error = {error:.6e}")
+
+if __name__ == '__main__':
+    raw_input = input("Enter resistor values (floats) separated by spaces or commas: ")
+    resistors = [float(x) for x in raw_input.replace(',', ' ').split() if x.strip()]
+    while True:
+        try:
+            desired_ratio = float(input("Enter desired ratio (0<ratio<=1): "))
+            if 0 < desired_ratio <= 1:
+                break
+            else:
+                print("Invalid ratio.")
+        except ValueError:
+            print("Invalid input.")
+
+    find_bests(desired_ratio, resistors)
+