better math?

spice/Draft1.asc

@@ -0,0 +1,2 @@
+Version 4.1
+SHEET 1 880 680

spice/available-resistors.csv

@@ -0,0 +1,26 @@
+Value (Ohms),Pieces,Tolerance
+1,40,5.00%
+2.2,40,5.00%
+3.3,40,5.00%
+10,40,5.00%
+22,40,5.00%
+47,40,5.00%
+68,40,5.00%
+100,40,5.00%
+120,40,5.00%
+150,40,5.00%
+220,40,5.00%
+330,40,5.00%
+470,40,5.00%
+560,40,5.00%
+680,40,5.00%
+1000,40,5.00%
+2000,40,5.00%
+2200,40,5.00%
+4700,40,5.00%
+5600,40,5.00%
+10000,40,5.00%
+22000,40,5.00%
+47000,40,5.00%
+100000,40,5.00%
+1000000,40,5.00%

spice/rvals-theory1.md

@@ -0,0 +1,61 @@
+# Resistor Values and Combinations
+
+The schematic calls for resistor values that are not available to us without some light sorcery. This is an attempt.
+
+Every resistor from the pack is rated for 0.25W and has a tolerance of $\pm5%$. Want to figure out how that could affect my calculations? Me neither.
+
+## 90Hz-110Hz
+
+### low-pass
+$(120 \parallel 47) + 3.3 = 37.072 \Omega$
+
+### high-pass
+$(68 \parallel 47) + (470 \parallel 2.2) = 28.245 \Omega$
+
+## 290Hz-310Hz
+
+### low-pass
+$(220 \parallel 68) + 2.2 + 1 = 55.144 \Omega$
+
+### high-pass
+Luckily, we already have 47 $\Omega$ resistors.
+
+## 950Hz-1050Hz
+
+### low-pass
+$(22 \parallel 47) + 2.2 = 17.186 \Omega$
+...or alternatively:
+$(10 \parallel 10) + 10 + 1 + 1 = 17 \Omega$
+
+### high-pass
+$(10 \parallel 10) + 10 = 15 \Omega$
+
+## 3.2kHz - 3.4kHz
+
+## low-pass
+$47 + 1 + 1 = 49 \Omega$
+
+## high-pass
+$22 + 22 + 1 + 1 = 46 \Omega$
+
+...no one ever said we had to be clever.
+
+## 9khz - 11khz
+
+## low-pass
+$(10 \parallel 10) + (68 \parallel 3.3) + 10 = 18.147 \Omega$
+
+## high-pass
+$(22 \parallel 22) + 1 + 1 + 1 = 14 \Omega$
+
+---
+
+# Bonus: some fun(?) and useful(?) resistor values
+
+$(10 \parallel 10) = 5 \Omega$
+
+$(220 \parallel 22) = 20 \Omega$
+
+$(22 \parallel 22) = 11 \Omega$
+
+$(100 \parallel 150) = 60 \Omega$

spice/rvals-theory2.md

@@ -0,0 +1,48 @@
+# Resistor Values and Combinations
+
+...with reducing resistor count as a priority.
+
+This time not while half-asleep.
+
+## 90Hz-110Hz
+
+### low-pass
+$(120 \parallel 47) + 3.3 = 37.072 \Omega$
+
+### high-pass
+$(68 \parallel 47) + (470 \parallel 2.2) = 28.245 \Omega$
+
+## 290Hz-310Hz
+
+### low-pass
+$22 + 22 + 10 + 1 = 55 \Omega$
+
+### high-pass
+$47 \Omega$ resistors are already available.
+
+## 950Hz-1050Hz
+
+### low-pass
+$((68 \parallel 68) \parallel (68 \ parallel 68)) = 17 \Omega$
+
+### high-pass
+$(10 \parallel 10) + 10 = 15 \Omega$
+
+## 3.2kHz - 3.4kHz
+
+## low-pass
+$47 + 1 + 1 = 49 \Omega$
+
+## high-pass
+$22 + 22 + 1 + 1 = 46 \Omega$
+
+## 9khz - 11khz
+
+## low-pass
+$(10 \parallel 10) + (47 \parallel 3.3) + 10 = 18.083 \Omega$
+
+## high-pass
+$(22 \parallel 22) + 1 + 1 + 1 = 14 \Omega$ (better tolerance)
+
+Alternative: $10 + 1 + 1 + 1 + 1 = 14 \Omega$ (worse tolerance)
+