*

1 files changed, 79 insertions, 0 deletions

diff --git a/js/games/nluqo.github.io/~bh/61a-pages/Lib/resist.scm b/js/games/nluqo.github.io/~bh/61a-pages/Lib/resist.scm
new file mode 100644
index 0000000..42c0e6b
--- /dev/null
+++ b/js/games/nluqo.github.io/~bh/61a-pages/Lib/resist.scm
@@ -0,0 +1,79 @@
+(define (make-resistor resistance)
+  (attach-type 'resistor resistance))
+
+(define (resistor? ckt)
+  (eq? (type ckt) 'resistor))
+
+(define (make-series ckt1 ckt2)
+  (attach-type 'series (list ckt1 ckt2)))
+
+(define (series? ckt)
+  (eq? (type ckt) 'series))
+
+(define (make-parallel ckt1 ckt2)
+  (attach-type 'parallel (list ckt1 ckt2)))
+
+(define (parallel? ckt)
+  (eq? (type ckt) 'parallel))
+
+
+(define (resistance ckt)
+  (cond ((resistor? ckt)
+	 (resistance-resistor (contents ckt)))
+	((parallel? ckt)
+	 (resistance-parallel (contents ckt)))
+	((series? ckt)
+	 (resistance-series (contents ckt)))))
+
+(define (conductance ckt)
+  (cond ((resistor? ckt)
+	 (conductance-resistor (contents ckt)))
+	((parallel? ckt)
+	 (conductance-parallel (contents ckt)))
+	((series? ckt)
+	 (conductance-series (contents ckt)))))
+
+
+(define (resistance-resistor resistor)
+  resistor)
+
+(define (conductance-resistor resistor)
+  (/ 1 (resistance-resistor resistor)))
+
+
+(define (resistance-series ckt)
+  (+ (resistance (left-branch ckt))
+     (resistance (right-branch ckt))))
+
+(define (conductance-series ckt)
+  (/ 1 (resistance-series ckt)))
+
+(define (conductance-parallel ckt)
+  (+ (conductance (left-branch ckt))
+     (conductance (right-branch ckt))))
+
+(define (resistance-parallel ckt)
+  (/ 1 (conductance-parallel ckt)))
+
+
+
+(define left-branch car)
+(define right-branch cadr)
+(define attach-type cons)
+(define type car)
+(define contents cdr)
+
+
+
+(define (repeated f n)
+  (lambda (x)
+    (if (= n 0)
+	x
+	((repeated f (-1+ n)) (f x)))))
+
+(define (L-extend base series-part parallel-part)
+  (make-series series-part (make-parallel parallel-part base)))
+
+(define (ladder-extension stages base series-part parallel-part)
+  ((repeated (lambda (x) (L-extend x series-part parallel-part)) stages)
+   base))