diff --git a/crates/applications/buffer_proto5/src/main.rs b/crates/applications/buffer_proto5/src/main.rs
index d8782b8..436ff97 100644
--- a/crates/applications/buffer_proto5/src/main.rs
+++ b/crates/applications/buffer_proto5/src/main.rs
@@ -22,7 +22,7 @@ use coremem::real::{R32, Real as _};
 use coremem::render::CsvRenderer;
 use coremem::sim::spirv::{SpirvSim, WgpuBackend};
 use coremem::sim::units::{Seconds, Time as _};
-use coremem::stim::{CurlVectorField, Exp1, Gated, ModulatedVectorField, Sinusoid, StimExt as _};
+use coremem::stim::{CurlVectorField, Exp, Gated, ModulatedVectorField, Sinusoid, StimExt as _};
 use log::{error, info, warn};
 use serde::{Deserialize, Serialize};
 
@@ -456,7 +456,7 @@ fn run_sim(id: u32, p: Params, g: Geometries) -> Results {
     };
 
     let add_drive_exp_pulse = |driver: &mut Driver<_>, region: &Torus, start: f32, duration: f32, amp: f32| {
-        let wave = Exp1::new_at(amp, start, 0.5*duration);
+        let wave = Exp::new_at(amp, start, 0.5*duration);
         driver.add_stimulus(ModulatedVectorField::new(
             CurlVectorField::new(region.clone()),
             wave,
diff --git a/crates/applications/multi_core_inverter/src/main.rs b/crates/applications/multi_core_inverter/src/main.rs
index ed4eae8..718039f 100644
--- a/crates/applications/multi_core_inverter/src/main.rs
+++ b/crates/applications/multi_core_inverter/src/main.rs
@@ -43,7 +43,7 @@ use coremem::meas;
 use coremem::real::{self, Real as _};
 use coremem::sim::spirv::{self, SpirvSim};
 use coremem::sim::units::Seconds;
-use coremem::stim::{CurlVectorField, Exp, Gated, ModulatedVectorField, Shifted, StimExt as _};
+use coremem::stim::{CurlVectorField, Exp, Gated, ModulatedVectorField, Scaled, Shifted, StimExt as _};
 use coremem::Driver;
 
 type R = real::R32;
@@ -76,7 +76,7 @@ enum ClockState {
     ReleaseLow,
     Float,
 }
-type ClockSegment = Shifted<Gated<Exp<f32>>>;
+type ClockSegment = Shifted<Gated<Scaled<Exp, f32>>>;
 
 impl ClockState {
     fn time_stimulus(&self, params: &Params, cycle: u32)
diff --git a/crates/coremem/src/stim.rs b/crates/coremem/src/stim.rs
index 1c38050..47cdeb7 100644
--- a/crates/coremem/src/stim.rs
+++ b/crates/coremem/src/stim.rs
@@ -475,50 +475,27 @@ impl TimeVarying for Sinusoid {
     }
 }
 
-/// E field with magnitude that decays exponentially over t.
+/// E field that decays exponentially over t.
 #[derive(Clone)]
-pub struct Exp<A> {
-    amp: A,
+pub struct Exp {
     tau: f32,
 }
-pub type Exp1 = Exp<f32>;
 
-impl<A> Exp<A> {
-    pub fn new(amp: A, half_life: f32) -> Self {
+impl Exp {
+    pub fn new(half_life: f32) -> Self {
         let tau = std::f32::consts::LN_2/half_life;
-        Self { amp, tau }
+        Self { tau }
     }
 
-    pub fn new_at(amp: A, start: f32, half_life: f32) -> Shifted<Gated<Self>> {
-        Shifted::new(
-            Gated::new(
-                Self::new(amp, half_life),
-                0.0,
-                half_life*100.0
-            ),
-            start,
-        )
+    pub fn new_at(amp: f32, start: f32, half_life: f32) -> Shifted<Gated<Scaled<Self, f32>>> {
+        Self::new(half_life).scaled(amp).gated(0.0, half_life*100.0).shifted(start)
     }
 }
 
-impl<A: TimeVarying> TimeVarying for Exp<A> {
+impl TimeVarying for Exp {
     fn at(&self, t_sec: f32) -> FieldMags {
-        self.amp.at(t_sec) * (t_sec * -self.tau).exp()
-    }
-}
-
-impl<A: Stimulus> Stimulus for Exp<A> {
-    fn at(&self, t_sec: f32, feat_size: f32, loc: Index) -> Fields {
-        let scale = (t_sec * -self.tau).exp();
-        let inner = self.amp.at(t_sec, feat_size, loc);
-        Fields {
-            e: inner.e * scale,
-            h: inner.h * scale,
-        }
-    }
-    fn eval_into(&self, t_sec: f32, feat_size: f32, scale: f32, mut into: OffsetDimSlice<&mut [Fields]>) {
-        let my_scale = (t_sec * -self.tau).exp();
-        self.amp.eval_into(t_sec, feat_size, scale * my_scale, into.as_mut());
+        let a = (t_sec * -self.tau).exp();
+        FieldMags::new_eh(a, a)
     }
 }
 
@@ -616,6 +593,7 @@ impl<T: Stimulus> Stimulus for Shifted<T> {
 }
 
 
+#[derive(Clone)]
 pub struct Scaled<A, B>(A, B);
 
 impl<A, B> Scaled<A, B> {