hello i want to know that why he use a resistor R2 in parallel what its main funtion if i dont use it the circuit is not working plz help me to understand this circuit
http://3.bp.blogspot.com/-jjXyZ4-Yv...ng+Torch+Bulb%2C+Circuit+Diagram%2C+Image.jpg
http://3.bp.blogspot.com/-jjXyZ4-Yv...ng+Torch+Bulb%2C+Circuit+Diagram%2C+Image.jpg