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Relay

Control a Relay ON OFF Using SIM Card, Mobile Phone, and Arduino

Last Updated on May 25, 2026 by Swagatam 12 Comments

This project I will explain how we can control a relay remotely using a SIM card and a normal mobile phone, with help of Arduino and a GSM module. The relay can be turned ON or OFF by sending an SMS or by making a phone call to the SIM card placed inside the GSM […]

Filed Under: Arduino Projects, Automation Projects, Wireless Circuits Tagged With: Card, Control, OFF, ON, Relay, SIM

Make this Single MOSFET Solid-State Relay SSR circuit

Last Updated on April 15, 2026 by Swagatam 2 Comments

This single MOSFET solid-state relay SSR circuit is a very simple where you can drive an AC load like a lamp, motor, or any oter AC load, through a small DC control voltage. We use only one IRF840 MOSFET to switch the 220V AC load, and we do this with some clever diode bridge arrangement, […]

Filed Under: Voltage Control and Protection Tagged With: MOSFET, Relay, Single, Solid, SSR, State

DPDT Relay Working, Pinouts, Testing Explained

Last Updated on May 20, 2026 by Swagatam 23 Comments

In this post we are going to understand about how this DPDT relay actually works, how we identify its pinouts, and how we can use it in our projects. We shall go step by step so that you can feel confident with every small thing about it. Introduction We know that a DPDT relay means […]

Filed Under: Electronics Theory Tagged With: DPDT, Explained, Pinouts, Relay, Testing, Working

RC Snubber Calculator for MOSFETs, Relay Contacts and Triacs

Last Updated on September 15, 2025 by Swagatam 8 Comments

This calculator is basically finding out two things: …so that we can make a perfect RC snubber for killing high voltage spikes across: Now let us break down everything it’s calculating. RC Snubber Calculator Application Type: MOSFETTRIACRelay Contact Peak Voltage (V): Peak Current (A): Rise Time (µs): Calculate Snubber © homemade-Circuits.com Basic Snubber Formula Logic […]

Filed Under: Voltage Control and Protection Tagged With: Calculator, Contacts, MOSFETs, RC, Relay, Snubber

How to Connect 5V Relay Module: Testing and Interfacing

Last Updated on April 29, 2026 by Swagatam Leave a Comment

In this post we are talking about this handy little gadget called a 5V single-channel relay module. It is super useful for our microcontroller projects whether we are using Arduino, Raspberry Pi, or even the ESP8266/ESP32. Let us break it down together, what it is, how it works, and how we can connect it. Understanding […]

Filed Under: Timer and Delay Relay Tagged With: Channel, Connect, Module, Relay, Single

ON/OFF Relay Switch Circuit using Reflection Sensor

Last Updated on May 13, 2023 by Swagatam Leave a Comment

ON OFF switch circuit using IR reflection sensor CNY70

This 220 V ON/OFF electronic relay switch can be toggled ON/OFF simply by alternately bringing your finger close to the reflection sensor CNY70. About CNY70 CNY70 is an infrared reflecting sensor comprised of an infrared emitting diode and a phototransistor housed in a tiny plastic container. The sensor operates by generating infrared light and sensing […]

Filed Under: Sensors and Detectors Tagged With: OFF, ON, Reflection, Relay, Sensor, Switch

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