Add DC-bias C_eff stima to derating and INFO when bulk C has no HF ceramic.

Keep both as labelled estimates: no Murata lot curve and no invented Z(f) target without f_sw.

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/content/changelog.md

@@ -2,6 +2,14 @@
 
 What's new in Pinscope.
 
+## 2.13.0 — 2026-09-10 — DC-bias C_eff stima
+
+The derating table now shows an effective capacitance under DC bias for C0G/X7R/X5R ceramics. It is labelled *stima* — not a vendor lot curve.
+
+- [New] `C_eff` column from an empirical V/Vrated table. Tantalum/electrolytic and unknown dielectrics are left blank.
+- [Improved] C0G/NP0 stays at nominal C; X7R at 50% of rated V is about 70% of C.
+- [New] Bulk C without a ~100 nF ceramic is `PS-ESR-001` INFO (no invented Z(f) target).
+
 ## 2.12.0 — 2026-09-10 — Pull-up sizing and LDO Cout
 
 Deterministic schema checks now size I2C pull-ups, flag NRST pull-downs, and look at LDO VOUT capacitance — still WARNING, never a invented datasheet µF ERROR.

frontend/src/app/(app)/project/[id]/page.tsx

@@ -751,6 +751,9 @@ function DeratingTable({
               <span className="text-[10px] text-rose-600 dark:text-rose-400">{failCount} fail</span>
             )}
           </CardTitle>
+          <p className="text-[11px] text-muted-foreground pt-1">
+            C_eff is an empirical DC-bias stima (C0G/X7R/X5R), not a Murata lot curve.
+          </p>
         </CardHeader>
         <CardContent>
           <div className="overflow-x-auto">
@@ -760,6 +763,7 @@ function DeratingTable({
                   <th className="pb-2 pr-4 font-medium">Designator</th>
                   <th className="pb-2 pr-4 font-medium">MPN</th>
                   <th className="pb-2 pr-4 font-medium">Value</th>
+                  <th className="pb-2 pr-4 font-medium">C_eff</th>
                   <th className="pb-2 pr-4 font-medium">Type</th>
                   <th className="pb-2 pr-4 font-medium">Net+</th>
                   <th className="pb-2 pr-4 font-medium">Net−</th>
@@ -800,6 +804,18 @@ function DeratingTable({
                       <td className="py-2 pr-4 font-mono text-xs">
                         {row.value_formatted ?? <span className="text-muted-foreground">—</span>}
                       </td>
+                      <td className="py-2 pr-4 font-mono text-xs">
+                        {row.c_eff_formatted ? (
+                          <span title="Empirical DC-bias stima, not a vendor lot curve">
+                            {row.c_eff_formatted}
+                            {row.dc_bias_model === "stima" && (
+                              <span className="ml-1 text-[10px] text-muted-foreground">stima</span>
+                            )}
+                          </span>
+                        ) : (
+                          <span className="text-muted-foreground">—</span>
+                        )}
+                      </td>
                       <td className="py-2 pr-4 text-xs">
                         {row.dielectric_category ? (
                           <Badge variant="outline" className="text-[10px] px-1.5 py-0 capitalize">

frontend/src/lib/types.ts

@@ -305,6 +305,12 @@ export interface DeratingRow {
   net_plus: string | null;
   net_minus: string | null;
   dielectric_category: "ceramic" | "tantalum" | "electrolytic" | null;
+  dielectric?: string | null;
+  c_nominal_f?: number | null;
+  dc_bias_factor?: number | null;
+  c_eff_f?: number | null;
+  c_eff_formatted?: string | null;
+  dc_bias_model?: "stima" | null;
 }
 
 export interface DeratingSettings {