A lateral sliding-mode TENG pairs two flat plates of length L, width W: one coated with an electron-attracting polymer (e.g. PTFE), the other a metal electrode. Rubbing them once transfers a fixed triboelectric surface charge density σ onto the polymer (a material property from the triboelectric series — it does not change as the device runs). As the top plate slides back and forth by displacement x(t), the un-covered strip exposes bound charge, and free electrons in the fixed electrode redistribute (electrostatic induction) to screen it — that redistribution, driven through an external load, is the harvested current.
Overlap capacitance: C(x) = ε0·W·(L−|x|) / d_eff
Short-circuit charge: Qsc(x) = σ·W·|x|
Circuit equation: dQ/dt = (Qsc(x) − Q) / (R_L·C(x))
Load voltage: V(t) = I(t)·R_L
Instantaneous power: P(t) = I(t)²·R_L
This is the standard equivalent-circuit model used to characterise real TENGs (Niu & Wang et al.). The tiny device capacitance (picofarads) is why TENGs are high-voltage/low-current sources — open-circuit voltage can reach kilovolts even though the current stays in the nanoamp-to-microamp range. There is an optimal load resistance, near where R_L matches the device's average capacitive reactance, that maximises delivered power — sweep the RL slider and watch instantaneous power peak partway across the range rather than at either end.
- Material pair — sets σ (higher separation on the triboelectric series → larger σ → more charge, more power).
- Slide frequency — how fast the top plate reciprocates; higher speed = higher peak current (dQsc/dt scales with velocity).
- Plate length L — sets the stroke and the baseline capacitance scale.
- Load resistance RL — the external circuit the harvester drives; this is the single biggest lever on delivered power.