Dark Sensitive Circuit With C828 Transistor In Sinhala

අදුරට සංවේදී පරිපටයක් සකස් කර ගන්නා ආකාරය සරල සිංහලෙන්.



Dark sensitive circuits have a range of applications such as turning on lights when the light level falls below a certain threshold.In our circuit this threshold is changed by using a variable resistor which can be turned to fine tune the circuit.



The circuit consists of the following components:

C828 transistor x1

7805 voltage regulator x1

1 kilo ohms resistor x1

LDR x1

LED x1

100 kilo ohms variable resistor. 



The base current of the transistor is controlled by the potentiometer.In very low light conditions the ldr will have a very high resistance and in high light conditions the ldr will have a low resistance.In the dark condition less current will flow through the ldr so more current passes through the base of the transistor causing a high current flow through the led via the collector pin of the transistor causing the led to light up but in high light condtions the ldr will have a low resistance there for most of the current will flow through the ldr instead of the base of the transistor so causing the light to turn off in high light condtions.



The circuit can be developed to replace the led with a relay in order to control a high load according to the light conditions.

LDR stands for light dependent resistor which can be considered as the key component of this project as it detects the light available.