Dear All,
I would like to know that; Is resistor R10 required for following circuit.
Conditions;
the circuit has to be in a way such that;
1. Each LED gets constant current of 20mA in ON state, irrespective of how many LEDs are ON (conducting) at any given time.
2. Transistor's Collector current is 300mA and is supplied by constant Base current in Fully Saturated state (ON).
This question is bugging my mind...
Do I need an extra resistor(R10) in parallel to other LEDs to bypass excess current drawn by collector? Or is it not required?
Considering Collector/emitter current is 300mA and 8 LED consumes 20mA x 8= 160mA so what will happen to the rest of 140mA?
I would like to know that; Is resistor R10 required for following circuit.
Conditions;
the circuit has to be in a way such that;
1. Each LED gets constant current of 20mA in ON state, irrespective of how many LEDs are ON (conducting) at any given time.
2. Transistor's Collector current is 300mA and is supplied by constant Base current in Fully Saturated state (ON).
This question is bugging my mind...
Do I need an extra resistor(R10) in parallel to other LEDs to bypass excess current drawn by collector? Or is it not required?
Considering Collector/emitter current is 300mA and 8 LED consumes 20mA x 8= 160mA so what will happen to the rest of 140mA?