In many electronic circuits, wrong battery connection can damage sensitive components, therefore, a Simple Reverse Polarity Protection Buzzer Alarm Circuit gives an early warning before damage happens. This circuit is simple, low cost and easy to build, also it uses common parts like diode, resistor, LED and buzzer. When we connect the supply in the […]
Alarm Circuits
Simple LDR Based Refrigerator Door Warning Circuit
In our previous post, we designed a Refrigerator Door Open Alarm Circuit with IC 555 but however, in this post, we design a Simple LDR Based Refrigerator Door Warning Circuit without using any IC. Moreover, this circuit helps to alert the user when the fridge door stays open for a long time, as this simple […]
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 […]
LDR Based Morning Alarm Circuit using NAND Gate IC
A LDR Based Morning Alarm Circuit using NAND Gate IC helps switch on an alarm sound automatically when morning sunlight falls on the sensor. This circuit uses an LDR (Light Dependent Resistor) and a CD4011 NAND gate IC to detect light and as soon as sunlight reaches the LDR, the resistance of the LDR changes. […]
Solar Sensor Based Security Alarm Circuit using Transistors
This is a simple and low-cost Solar Sensor Based Security Alarm Circuit using Transistors which uses a solar sensor for light sensing. The circuit gives alarm sound through the speaker when light level changes and it works mainly when darkness comes or when someone blocks light on the sensor. So we can use this circuit […]
Temperature Sensing Alarm Circuit using Buzzer
We already see many temperature detector circuits in out previous blogs, but in this project we show a simple temperature detector circuit, here we use LM335 temperature sensor as good sensor IC and TL071 op-amp IC as comparator. Now, the circuit senses temperature and then gives alert using buzzer when temperature crosses set level, so […]