In this post I have explained a very simple digital panel type voltmeter circuit using a single IC L7107 and a few other ordinary components. The circuit is able to measure voltages right up to 2000 AC/DC V. About the IC L7107 Making this simple digital panel voltmeter circuit is particularly easy due to the availability […]
Newly Updated Circuit Projects:
Making an Adjustable Electromagnet Circuit
This article describes a simple circuit which can be used for pulsing an electromagnet. The IC 555 once again becomes the central part of the circuit. I have explained the making procedure of this simple adjustable electromagnet circuit for varying the magnetic power of an electromagnet. Introduction The circuit was requested by Mr.Jason, one of […]
How to Make a Bridge Rectifier
A bridge rectifier is an electronic network using 4 diodes which is used for converting an AC input to DC output. The process is called full wave rectification. Here I have explained the basic working principle of rectifier diodes such as a 1N4007 or a 1N5408, and also learn how to connect 1N4007 diodes to […]
SCR Shunt Circuit for Protecting LED Drivers
The post presents an effective method for protecting capacitive LED driver circuits through an SCR shunt regulator circuit and explains how it can prevent filter capacitors from blowing of and LEDs from getting destroyed. The remedy was requested by Mr. Max Payne. Protecting High Watt LEDs Please suggest regarding 3W, 5W LED bulb circuit design fault. […]
MQ-135 Air Quality Sensor Circuit – Working and Interfacing with Program Code
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 […]
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 […]





