An Simple AC Mains Presence Indicator Circuit helps us check whether AC mains supply is present at the input and whether power reaches the load side. This circuit is easy, low-cost and very useful for home appliances, control panels, extension boards and industrial systems. In this circuit, two LEDs show two different conditions, first LED1 […]
Indicator Circuits
Simple Neon Lamp Fuse Blow Alarm Circuit
This post is for a Simple Neon Lamp Fuse Blow Alarm Circuit which helps us know when the fuse in the AC mains line gets open or blown. Normally, when the fuse is healthy, current flows through it and the load works in normal condition, when the fuse blows, the load stops working but at […]
Fuse Blown Status Indicator Circuit for 12V DC Supply
In many 12V power supply systems, fuse protection plays an important role, a fuse protects the load and other circuit parts from overcurrent and short circuit. However, sometimes the fuse blows and we do not know immediately, because of this the connected load stops working and so this Fuse Blown Status Indicator Circuit for 12V […]
Simple SCR Based Low Battery Display Circuit
A Simple SCR Based Low Battery Display Circuit helps us know when the 9V battery voltage drops near the critical level. For example, if the 9V battery level reaches 8.3V or 8.6V then the LED glows and because of this, the user can replace the battery before the connected device stops working. This circuit uses […]
Diode Tester Circuit using Op-Amp and LED
In this tutorial, we build a simple diode testing circuit which is very useful for beginners in electronics as it gives good learning and practical use. Normally, we use a multimeter to test a diode easily but sometimes a normal meter does not test all diode types properly. For example, a Schottky diode works on […]
Car Engine Heat Detector Circuit with Sound Alert
Like in previous post on Automobile Engine Overheat Alert Circuit using LED, where driver gets indication through LED, but in this circuit, driver gets alert through sound and this sound comes from IC 555, which works as astable multivibrator and generates sound signal, also we can adjust temperature level for alarm using variable resistor which […]