Typical Fuel Tank Pressure Sensor Circuit

Here’s a design circuit for the control module monitors the fuel tank pressure (FTP) sensor signal in order to detect vacuum decay and excess vacuum during the enhanced evaporative emission (EVAP) diagnostic. This is the figure of the circuit;

The Fuel Tank Pressure Sensor responds to changes in the fuel tank pressure or vacuum. This information is used in order to detect vacuum decay or an excessive vacuum during EVAP diagnostic routing. The fuel tank pressure sensor signal voltage to the VCM varies from a minimum of about 0.1 volts with pressure in the fuel tank to above 4.0 volts with a high vacuum in the fuel tank.

Mass Air Flow MAF Sensor Circuit

This is a design circuit for mass air flow sensor circuit. The mass air flow sensors converts the amount of air drawn into the engine into a voltage signal. The primary components of the MAF sensor are thermistor, a platinum hot wire, and an electronic control circuit. The thermistor measures the temperature of the incoming air. This is the figure of the circuit;

The hot wire is maintained at a constant temperature in relation to the thermistor by the electronic control circuit. An increase in air flow will cause the hot wire to lose heat faster and the electronic control circuitry will compensate by sending more current through the wire.

Simple Provide Remote Alarm for Smoke Detector Circuit

Here’s a design circuit for an application from Maxim Semiconductor Application Notes. Nowadays, due to efficiency and low cost, ionization-based smoke detector are often installed in the buildings, houses, and garages. The device is placed far away from the house. Therefore, we need to transmit the alarm signals back into the central security system. This is the figure of the circuit;

The Integrated Circuit MAX921 is used as a comparator. The properties of this IC are have low supply current, internal voltage reference, and wide supply-voltage range. The typical value of currents are 50uA during monitor mode. When the sounder is active, the value of the current is 3mA. This circuit gains power from the smoke detector’s battery. This circuit has an output of an open-drain FET, which will trigger an RF module that communicates or drive the home-security system back to the residence.