piezo_pickup_and_mosfet_source_follower.ngjs

#!/usr/bin/env ngspicejs
// Piezo pickup with mosfet source follower as input buffer
// linter: ngspicejs-lint
"use strict";

// first we connect resistor directly to 50k load and show AC
pickup_piezo('U1', 4, 0);
resistor('R5', 4, 0, '50k');
var a1 = ac().fstop('5k').run();
echo('Piezo directly driving 50k resistive load:');
a1.chart('V(4)');

// then we make mosfet source follower
netlist_clear();
pickup_piezo('U1', 1, 0);
capacitor('C1', 1, 5, '100n');
capacitor('C2', 5, 0, '10p');
resistor('R1', 7, 5, '10M');
resistor('R2', 5, 0, '10M');
mosfet_n('T1', 7, 5, 3, 'BS170');
resistor('RS', 3, 0, '20k');
capacitor('C3', 3, 4, '47u');
resistor('R5', 4, 0, '50k');
battery('U2', 7, 0, 9);
a1 = ac().fstop('5k').run();
echo('Piezo driving 50k resistive load via mosfet source follower:');
a1.chart('V(4)');