Resistance & Pressure Drop

Squeeze the pipe to add resistance and watch pressure drop across it
Source (voltage in) 0 PSI Gauge A before Resistor (narrow pipe) 0 PSI Gauge B after valve open Load Pressure drop across resistor
Wide pipe Narrow pipe
Resistance: 30%  |  Gauge A: 72%  |  Gauge B: 50%
Flow: moving
Vdrop = I × R  —  the more resistance, the bigger the pressure difference between Gauge A and Gauge B for the same flow
Narrow pipe section = resistance (ohms)
Gauge A vs Gauge B = voltage before/after the resistor
Gap between gauges = voltage drop
Flow speed = current (amps) — slows as resistance rises
Valve shut at the end = no current — no drop across resistor, both gauges equalize