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What type of gauge should I get, mechanical or electrical?

Mechanical Gauges:
Mechanical gauges do not require power to operate.They can use power for lighting purposes though.They make direct physical contact with the item they are reading.Mechanical gauges can have noise to them. Some might have a slight rattle as there are moveable gears, pins, or pivot points inside which may cause noise.Can have a jumpy or have an erratic sweep.Generally less expensive.

Electrical Gauges:
No large connectors and tubing coming out the back. Can be mounted in more unusual positions without connections showing. Easier to install in tight areas. Easier to install a great distance from the item being measured. Stops fluids from entering the passenger compartment. The pointer sweep is more smooth and seamless.Generally more expensive.

What does a Boost Sensor do?

Boost pressure sensors are used in turbocharged engines to provide air pressure information and air and fuel ratios in order to regulate engine performance. As a complex piece of technology, a boost pressure sensor has been an impressive addition to engine technology. Boost pressure sensors control the boost level produced in the intake manifold of a turbocharged or supercharged engine. They affect the air pressure delivered to the pneumatic and mechanical wastegate actuator.

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What is the working principle of the reed liquid level sensor?

The reed level sensors come in all different packages, but each sensor includes a housing that incorporates the reed switch and any circuitry along with wires to make the electrical connections to an external circuit. Also included is a float that contains a permanent magnet. The float can be part of the housing where it would ride up and down along the extension or stem of the housing. Floats can also be completely separate from the housing giving complete versatility to the sensor. When the float is in proximity to the reed switch, the contacts will sense the magnetic force closing the contacts.

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Which Exhaust Gas Temperature Sensors Should I Choose ?

Summary :  The main measurement methods used for the determination of exhaust gas temperatures include resistance temperature sensors and thermocouples. Resistive sensors commonly used for engine exhaust gas applications include platinum resistance sensors, such as Pt200, and NTC thermistors. A voltage divider circuit is used for signal processing for Pt200 and NTC sensors. Depending on the application, sensors with open or enclosed housing can be used.



In modern internal combustion engines, the knowledge of the exhaust gas temperature (EGT) is necessary for the management and diagnosis of the exhaust gas aftertreatment system, as well as for the protection of components that may be sensitive to thermal overloads.

In the diesel engine, aftertreatment components that are often actively managed based on exhaust gas temperature include diesel particulate filters (DPF) and NOx reduction catalysts such as SCR catalysts and NOx adsorber catalysts (NAC/LNT). In stoichiometric petrol engines, the engine management strategy depends on the temperature of the three-way catalyst (TWC). Examples of components that may require protection from thermal overload include turbochargers, EGR system components, as well as emission control catalysts.

Classification. In engine applications, two main measurement methods have been used for the determination of exhaust gas temperatures [McGee 1991]:

  • Resistance temperature sensors
  • Thermocouples

In resistance temperature sensors, an electrical resistance is generated which correlates with the sensor temperature. Here we differentiate between positive and negative temperature coefficients. In the case of negative temperature coefficients, ohmic resistances decrease as the temperature increases. Therefore, these sensors are referred to as NTC (negative temperature coefficient). Due to the fact that in a hot temperature range, their resistance falls to a fraction of the cold resistance, they are also referred to as “hot conductors”. Another alternative designation is “thermistor”, a portmanteau of “thermal resistor”.

In contrast to this, there are temperature sensors with increasing resistance values at simultaneously increasing temperatures [Carstens 2001]. Some of these are so-called PTC thermal resistors (positive temperature coefficient), mainly based on semiconductors, polycrystalline ceramics (e.g., barium titanate) which, on exceeding a limit temperature, abruptly increase their resistance and therefore are ideal for use as inrush current limiters and switch-off temperature limiters. These are also often referred to as thermistors. On the other temperature sensors in this category, platinum elements are used. These are known in industrial measuring technology as platinum resistance temperature detectors (PRTD), designated as Pt100 through Pt1000 in the DIN EC 60751 standard.

KTY is a trade name for PTC temperature measurement resistors based on semi-conductors. These temperature resistors based on silicon have a characteristic curve which is comparable to that of platinum elements. Their application temperature range reaches up to 300°C, which is why these construction elements are not of interest for use in exhaust gas flows, and are not further considered in the following text. The same applies for PTC thermistors, which can only be used up to around 150°C.

In thermocouples, the other major class of EGT sensors, the temperature measurement is based on the Seeback effect where a voltage is generated across the junction of two conductors of different metals in the presence of a temperature gradient. Different types of thermocouples exist, depending on the combination of metals that is used.

The classification of resistive and thermocouple-based temperature sensors is summarized in Table 1. As apparent from the table, sensor technologies suitable for exhaust gas applications include NTC thermistors, Pt resistance sensors, and Type N thermocouples.

Table 1
Classification and application of resistive and thermocouple temperature sensors
Type of SensorTemperature Range*Typical Applications
Resistor—NTC NTC thermistor -40°C ... +1000°C Diesel TC/DOC/DPF/SCR/NAC
Resistor—PTC PTC thermistor ≤ 150°C Current limiter on PCB
Pt resistance sensor -40°C ... +1050°C TC/TWC/DOC/DPF/SCR/NAC
KTY sensor ≤ 300°C Engine coolant, oil, ambient temperature, climate control
Thermocouple Type N -40°C ... +1100°C TC/TWC/DOC/DPF/SCR
Type K -40°C ... +1200°C Test bench, testing in general
TC = turbocharger; DOC = diesel oxidation catalyst; TWC = three-way-catalyst; DPF = diesel particulate filter; SCR = selective catalytic reduction; NAC = NOx adsorber catalyst; PCB = printed circuit board
* Applicable to the sensor technology—a particular sensor model may not cover the entire range.


Source: Exhaust Gas Temperature Sensors Author: Stefan Carstens


See our Exhaust Temperature Sensor Thermalcouple EGT Probe EGT exhaust gas temperature #exhaust gas


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Why Air Pressure Gauge does not go back to ZERO when I deflate the air ?

Why Air Pressure Gauge does not go back to ZERO when I deflate the air ?

To see weather where the problem is, see followings for testing steps for reference. 

In this case, we described the case with Dual Air Pressure gauge. 
Scenario: Dual Air Pressure Gauge, top readouts stays at 2psi after deflation and does not go back to ZERO readouts. (Check the problem is from gauges, sensors, or air suspension system)

1. Turn the power ON. (After installation completed) Trying to re-occur the situation. 

2. Deflate the upper airbag to see if it stays at 2psi. If the readouts stays at 2psi, unplug the bottom pressure sensor and switch to the upper one. If the gauge can drop to ZERO, means the gauges and sensors are working. There is air left after deflation. 


AirPressureGauge AirSuspensionGauge DualAirPressureGauge AirRideGauge AirbagSuspensionGauge

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What is an AIR CORE GAUGE ?

An air core gauge is a specific type of rotary actuator in an analog display gauge that allows an indicator to rotate a full 360 degrees. It is used in gauges and displays, most commonly automotive instrument clusters.

A typical automotive application is shown at the right. The air core gauge is a type of "air-core motor". It may be considered a "gauge movement" or "pointer indication device". 

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Why does my digital pressure readouts fluctuate up and down?

Wiring the two 12V power line separately from the gauges to sensors.


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Do you supply replacement bezels as I have damaged mine ?

Since the bezels are actually machine pressed on, we do not offer them separately as an accessory or service item. We can replace a damaged bezel, but it would have to come into our factory in the Taiwan for that service.