Circuit Current: How to Calculate IA, IB, IC, ID

[sandeep agari]

hello,
while making a circuit ( uploaded pic) ,the specifications of leds are 50mA/2V, i found the current ( ID )just before the leds to be around 180mA. i just want to know how to determine the currents in the circuit at various points( IA, IB , IC, ID). in general i want to know how to determine how a circuit draws current . do we have to take care of only voltage speciafications, voltage drops only and it will draw current automatically? just confused with the current calculations in this circuit. i hope if this will be cleared then it will help a lot in all others:) must respond.

 

[Simon Bridge]

Welcome to PF;
The circuit powered from a voltage source will draw a current automatically (up to the limits of the equipment)... potential difference and current are related.
Typically you would model the real-life circuit as a circuit of ideal components - for this you need to know the equivalent impedences of the real components and how to model them as ideal components. How far you take it depends on how much detail you need.