Light Sensitive Switch with LDR 2N2926

This circuit activates a warning when it becomes dark, functioning as a light-sensitive switch. The essential electronic components include the 2N2926 and AC128 transistors.

The described light-sensitive switch circuit is designed to detect ambient light levels and activate an output signal when the light intensity falls below a certain threshold. The core components of this circuit are the 2N2926 and AC128 transistors, which serve as the primary switching elements.

The operation of the circuit begins with a light-dependent resistor (LDR) that senses the light level. The LDR is connected in a voltage divider configuration with a fixed resistor. As the ambient light decreases, the resistance of the LDR increases, causing the voltage at the junction of the LDR and the resistor to rise. This voltage is fed into the base of the 2N2926 transistor.

The 2N2926 is configured as a switch. When the voltage at its base exceeds a certain threshold, the transistor turns on, allowing current to flow from the collector to the emitter. This current can be used to activate an alarm or indicator light, signaling that it is dark. The AC128 transistor may be used in conjunction with the 2N2926, possibly in a Darlington pair configuration, to amplify the current and improve the sensitivity of the circuit.

Additional components may include capacitors for noise filtering and diodes for protecting against reverse polarity. The circuit can be powered by a standard DC power supply, with appropriate voltage and current ratings to ensure reliable operation of the transistors.

This circuit can be applied in various applications, such as outdoor lighting systems, security alarms, or automatic night lights, providing a simple yet effective solution for light detection and response.This be circuit warn when be become dark, or Light sensitive switch. By use electronics part the base is important , be the transistor 2N2926 and AC128. For. 🔗 External reference