Simple LED Stopwatch Using IC 555 and IC 4017

In this post we are going to construct a simple LED stopwatch using IC 555 timer and IC 4017 decade counter. The elapsed time is indicated by LEDs which illuminates in a sequence. Stopwatch is very important piece of equipment in sports, cooking, laboratory, medical etc. They are used to measure short period of time […]

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Road Diversion Warning Indicator using Running LED Lights

The discussed LED lamp chaser circuit can be effectively used for indicating or warning road diversions or when a roadwork is in progress, especially in areas where street lamps are absent and in accident prone dark roadways. Roadworks and highways are usually marked during the hours of darkness by yellow flashing lights. These may often […]

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Thermal Indicator Circuit for Heatsinks

The post details how to build a simple 3 LED thermal indicator circuit for heatsinks and other similar applications to quickly understand the level of heat on the selected surface through a sequential 3 LED panel. The temperature of a heatsink can be measured with a wet finger: if it sizzles, the temperature is too […]

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Doorbell With Memory Circuit

The post explains how to enahnce your doorbell with a circuit which would facilitate a doorbell with memory circuit and allow the user to know through an illuminated LED if somebody has pressed the doorbell button while he was out and unavailable at home. On situation it could be helpful to understand when a guest has […]

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Simple Temperature Indicator using BC547 Transistor

The post explains a simple temperature indicator circuit using a single BC547 transistor and complementary 1N4148 diode. The temperature indication of a heat sink on a power transistor in high power circuits can be extremely useful. A simple, inexpensive temperature indicator would be ideal for this purpose since accuracy is not an important factor. In […]

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Simple Lamp Flasher Circuit

In this post we learn how to make a simple miniature lamp flasher circuit using some inexpensive transistors, resistors and capacitors. Let’s learn the details below: A lamp flasher is a device which is designed and used for switching a connected lamp alternately ON/OFF at a certain given rate per second. Meaning, a lamp or […]

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Car Chasing LED Arrow Turn Signal Indicator Circuit

A very simple yet interesting Chasing LED arrow car tun signal indicator circuit is discussed in this article. The circuit uses just a single 10 stage Johnson’s decade counter IC 4017 and an UJT for executing a very interesting two pattern LED light chasing on the connected LEDs, which produce an impression of creating an […]

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How to Test a SCR

In this post we learn how to test a SCR whether it’s good or bad using a couple of simple circuit implementations Simple SCR testing circuit Referring to the diagram below initializing the shown normally-open “on” push to ON button connects the gate to the anode, enabling current coming from the negative lead of the […]

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Automatic Light Circuit for Washroom  

  Building an automatic light for washroom is not at all complex. All you need to do is to follow the steps as described in this report to get the derived result. Using an automatic switch would help to save electricity. Moreover, the system is designed in a way to run on lesser power, thereby […]

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How to Build a Door Bell with Memory Circuit

On occasion this could be helpful to understand when a potential user has visited your door steps as part of your absence. This is especially valid in the circumstance of an unplanned absence when a prospect is anticipated. Bafflement is the greatest upon these situations. The Door Bell with Memory circuit below really helps to […]

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