Soldering practice light-dependent circuit - 5 V relay, photoresistor

Product Overview

• Soldering exercise for building a light-dependent circuit with a relay
• 5 V power supply
• Light detection using photoresistors
• Switches the relay at defined light thresholds
• Switching logic built with discrete components
• Soldered on a stripboard

Product Description

This soldering exercise teaches you how to build a light-dependent circuit with 5 V relay control. The project combines the fundamentals of sensor technology, analog signal processing, and electromagnetic switches in a functional overall system. Phototransistors or photoresistors detect changes in ambient brightness and use discrete components such as transistors and comparators to activate the relay when the brightness exceeds or falls below a set threshold.

The circuit uses the light-sensitive properties of semiconductor components to convert analog measured values into digital switching signals. By soldering and wiring all components on the stripboard, you learn not only soldering techniques and safety, but also gain a practical understanding of how analog circuits work. The learning effect is enhanced by being able to trace the function of each individual component in the assembled circuit.

Typical applications include automating lighting based on daylight conditions, dusk control for outdoor lights, or activating devices once a certain brightness threshold is reached. The switching logic can also be used as an addition to a motion detector or to control greenhouse conditions. In the classroom, the exercise serves as an introduction to sensors and an understanding of control loops.

The project requires basic soldering skills and a soldering iron with accessories. A multimeter is useful for checking the connections and adjusting the light threshold using a trimmer potentiometer. All required components are already included; no additional purchases are necessary.

Safety Information

Soldering requires careful handling of the hot soldering iron and adequate ventilation to protect against solder fumes. This project is intended exclusively for building prototypes and for testing and development purposes, and is not suitable for installation in household electrical circuits. If you are unsure about extending the circuit or before operating it on external electrical circuits, consult a qualified electrician.