Free Circuit Diagram

Introduction Interfacing humidity sensor can be difficult because of the sensor’s drive requirement and their wide dynamic range.  We can customize the circuit to obtain reasonable accuracy within the chosen range by carefully selecting the devices that comprise the analog front end. Here  we present a case study to design analog signal conditioner for [...]

You can use a humidity sensor to give an alert of boat leakage, or when your books start being flooded by heavy rain attack on your broken roof, or anything you can imagine. A simple humidity sensor (a humidity probe) can be constructed using two copper wires placed as close as possible to each other, [...]

In some temperature-sensing applications there are some problems caused by the placement of sensors on location where the potential is very different from that of the data-acquisition-system common. So the operating temperature sensor must be isolated from its data-acquisition system galvanically.  And the power’s source for the sensor was isolated. This circuit is designed to [...]

Current loop interface has been widely used in industrial environment because it’s robustness. Noise resistance and fail detection capability  made it suitable for long distant transmission in harsh environment. This circuit provide current loop transmitter for temperature sensor. Here is the circuit’s schematic diagram: The temperature measurement is done by LM35 temperature sensor [...]

For any electrically conductive liquid level measurement, this single chip circuit is very compact and simple. This circuit is an ac excited fluid level sensor, which uses alternating current to provide biasing for the sensor probe to avoid electrolysis of the probes.  This ac excitation makes the sensing probe has longer lifetime. This circuit can [...]

This pin diagram will be  useful when viewing these connectors. Sometimes you hold a soldering iron to the back of the connector, and you don’t remember the numbering of the pin. Here is the pin diagram for your reference: The number of each pins are actually  stamped on both sides of any D-type [...]