Gauge Indicators (Non-Electronic) Gauges

Automotive vehicles use two basic styles

Two Styles of Gauges BIMETALLIC GAUGESBIMETALLIC GAUGES –Thermo-electric –Slow Movement –U-Shaped Strip –Free Arm contains a heater. –Heat through coil distorts strip –More Current deflects needle more ELECTROMAGNETIC GAUGESELECTROMAGNETIC GAUGES –Four Types –d’Arsonval –Three-coil –Two-coil –Air core

Bimetallic Type

Balancing Coil Type Balancing Coil Type

THREE COIL GAUGE

AIR CORE GAUGE

d’ Arsonval Gauge

Constant Voltage Regulator Steady 5 voltsSteady 5 volts –Why?

TYPICAL TEMP GAUGE

FUEL GAUGE SYSTEM

SENDING UNITS THREE TYPESTHREE TYPES –THERMISTOR High Engine Temp = Resistance decreasesHigh Engine Temp = Resistance decreases –PIEZORESISTIVE Sensitive to Pressure ChangesSensitive to Pressure Changes Is a variable ResistorIs a variable Resistor –MECHANICAL VARIABLE RESISTOR Contains sliding contactsContains sliding contacts

PIEZORESISTIVE SENSOR

MECHANICAL VARIBLE RESISTOR

OIL PRESSURE WARNING LIGHT SENDING UNIT