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 […]
Security and Protection
Dual Threshold Voltage Comparator Circuit using IC LM741
A dual limit comparator is an important electronic circuit which compares one input voltage with two fixed voltage levels. In simple words, this Dual Threshold Voltage Comparator Circuit using IC LM741 checks whether the input voltage stays within a fixed range and it also checks whether the voltage crosses the upper limit or the lower […]
Simple AC Mains Presence Indicator Circuit
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 […]
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 […]
Simple 12V Protection and Soft Start Circuit
There are few protection circuit which we have shown in our previous post, but this article is for Simple 12V Protection and Soft Start Circuit for 12V systems. It helps to protect our load from sudden high current and voltage spikes and also, it gives a smooth start when power turns ON, because of this, […]
Automatic 12V Battery Charger Circuit with SCR Cutoff
This circuit is for Automatic 12V Battery Charger Circuit with SCR Cutoff, first it charges the battery and then it stops charging when the battery becomes full. Also, the circuit uses simple parts like transformer, diodes, SCR, resistor and capacitor and we can easily find these parts in market or online. So, this circuit protects […]