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 […]
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 […]
NTC Thermistor Based Temperature to Voltage Converter Circuit
In this article, a temperature to voltage converter circuit converts temperature change into proportional voltage output. An NTC thermistor senses the temperature and the 741 op-amp converts the resistance change into a voltage signal, as the temperature changes, the output voltage also changes in a linear way. Therefore, this NTC thermistor based temperature to voltage […]
Temperature Difference Based Relay Switch Circuit
A Temperature Difference Based Relay Switch Circuit compares the temperature of two different points and then switches a relay when the temperature difference reaches a set value. This circuit is useful in solar water heaters, cooling fans, battery temperature monitoring, incubators and industrial heat control systems. In this circuit, the LM741 operational amplifier works as […]
Op-Amp Based Diode Temperature Sensor Circuit
Temperature sensing is very important in electronic systems because many devices use temperature sensors to check heat and protect the circuit from damage. In this Op-Amp Based Diode Temperature Sensor Circuit, we used a simple 1N4148 diode as the sensing part and IC 741 as the signal processing unit. The circuit gives output voltage which […]