In this article I have explained how to interface air quality sensor MQ-135 with Arduino. We will see overview of the sensor and construct a project which detects LPG gas leakage and see some relevant readings in serial monitor. What is MQ-135 sensor? MQ-135 is an air quality or air pollution measuring sensor device. It […]
Newly Updated Circuit Projects:
RFID Security Lock Circuit – Full Program Code and Testing Details
In this article we will see how an Arduino based RFID reader circuit could be used for controlling a relay, which in turn could be used in security door lock applications. Overview If you haven’t yet checked the previous RFID article, please go ahead check it out, it covered the basics of RFID technology. We […]
Understanding Pull-Up and Pull-Down Resistors with Diagrams and Formulas
In this post I am going to explain pull-Up resistor and pull-down resistor, why they are commonly used in electronic circuits, what happens to electronic circuits without Pull-Up or Pull-down resistor, and How to calculate Pull-Up and Pull-down resistor values and finally we will see about open collector configuration. How Logic Inputs and Outputs Work […]
Lithium Polymer (Lipo) Battery Charger Circuit
In this post I have explained a simple lithium polymer (Lipo )battery with over charge cut off feature. The idea was requested by Mr. Arun Prashan. Charging a Single Lipo Cell with CC and CV I came across your work on “Bicycle Dynamo Battery Charger Circuit” in Homemade circuit design blog. It was really informative. I […]
Understanding PID Controller
The first successful assessment of PID control theory was practically verified in the field of automatic steering systems for ships, way back around the year 1920. After this it was applied in various industrial automatic process controls requiring optimized and accurate manufacturing output specifications. For manufacturing units PID was popularly implemented for achieving precise pneumatic […]
P-Channel MOSFET in H-Bridge Applications
Implementing P-channel MOSFETs in an H-bridge circuit may look easy and enticing, however it may require some stringent calculations and parameters for achieving an optimal response. P-channel MOSFETs are usually implemented for load ON/OFF switching. The ease-of-use of P-channel options on the high side allows them to be very convenient for applications like Low-Voltage Drives […]