In this post I have explained 9 LDR circuit projects that uses LDR light sensor to trigger a load ON/OFF through a relay. These circuits are mostly triggered by the absence or the presence of light on the LDR. The circuits are built using transistors, op amps and LDR along with a switching relay. Let’s […]
Explained
9 Simple Metal Detector Circuits Explained
In this post I have explained 9 simple metal detector circuits using LC tuned concept, magnetic absorption concept, and the beat frequency oscillator (BFO) concept. The BFO technique is considered to be the most accurate and reliable methods of detecting metals. 1) Metal Detector Circuit Using a Single UJT The first metal detector circuit shown […]
Simplest Combination Lock Circuit Explained
A electronic combination lock is a device which is designed to activate an electrical solenoid locking system whenever the correct combination of numbers are entered into an attached keypad. To build this type of electronic combination lock, normally an electronic circuit with a keypad is used. In the design I have explained in this article, […]
3 Useful Temperature Alarm Circuits Explained
In this post I have explained the working of 3 interesting and useful temperature alarm circuits through detailed circuit diagrams. A temperature alarm circuit is basically a device which is designed to detect a temperature threshold and sound an alarm as soon the temperature exceeds over, or drops below the desired temperature detection threshold. 1) […]
4 Automatic Day Night Switch Circuits Explained
The 4 simple light activated day night switch circuits explained here can all be used for controlling a load, normally a 220V lamp, in response to the varying levels of the surrounding ambient light. The circuit can be used as a commercial automatic street light control system, as a domestic porch light or corridor light […]
IC 7805, 7812, 7824 Pinout Connection Explained
In this post I have explained how to connect common 78XX voltage regulator ICs such as 7805, 7812, 7824 etc for getting fixed regulated output voltages at 5 V, 12 V, or 24 V outputs respectively. The input voltage must be at least 3 V higher than the desired output voltage. For example, if a […]