In this article I have explained a simple low battery indicator circuit using the IC 555 and a few resistors only. Circuit Concept Many electronic circuits such as emergency lights, battery chargers, UPS systems, flashlights etc essentially require a low battery indication feature in order to avoid over discharge of the involved battery. An over discharge could mean a permanent damage […]
Sensors and Detectors
Very Low Frequency (VLF) Detector Circuit
Low frequencies predominantly cover our earth’s atmosphere. This range of frequency may be created by many different sources which may be quite unknown and strange. A VLF sensor equipment can be made to trace these frequencies for investigating the intriguing secrets hidden behind it. Mr. Steven Chiverton investigates. VLF Receiver for Sensing Lightening and other […]
How to Make LED/LDR Opto Coupler
Ever needed an application where the resistance of a resistor needed to vary proportionately in response to a PWM or a varying analog voltage? Yes, this is where an LED-LDR opto-coupler becomes so useful. The following image shows the symbol for a LED LDR opto-coupler. Any other regular opto-coupler, such as an LED/transistor, LED/FET, or […]
Make this EMF Pump Circuit and Go Ghost Hunting
EMF pump circuits are devices which are popularly used for the purpose of identifying paranormal activities or entities by generating rapidly rotating magnetic fluxes in the ether. The conventional devices use a spinning magnet fixed over a motor spindle, however these are mechanical types and are prone to wear and tear. Introduction The explained circuit […]
Make this Thermo-Touch Operated Switch Circuit
The circuit explained here employs a rather different approach for implementing a touch operated switch action. Here instead of the resistance, the warmth of the finger is used for sensing and operating the circuit’s output. Irrespective of the ambient conditions, our hands and fingers mostly exhibits some extra warmth or increase in the level of […]
Make this Temperature Indicator Circuit with Sequential LED Display
In some of my earlier articles we have seen a few simple and interesting temperature indicator circuits, in this article we will try to upgrade one of them into a sequential form. All these circuits are useful in some or the other ways, however these are not equipped with step wise temperature level indicator arrangement […]