Designing circuit from scratch

Inspired by chotu bot model.
So started to explore circuit designing.
@Ashish_Pardeshi sir suggested to start with basic design of circuit for glowing small led light and also to find value of each component with drawing circuit on paper.

After finding value I started to make and collect things which I required to make circuit.
So, today I purchased the following things to start

Breadboard - 80₹
9V battery - 30₹
Resistance - 2₹
LED - 2₹
Battery cap - 5₹

So, their are two methods 2 find resistance value ohm’s law and krichoff law.
Let’s discuss this to improve basic foundation related to circuit.
@Farhan @ravi312 @jtd @G_N @ARYAN32


@Ashish_Pardeshi please help me to design workable circuit of light.
How to use kvl law to balance the resistance

Your reasoning looks okay, but not your calculations.

The forward voltage drop of the LED is (assume) 2 V.
Any voltage source you use to light it up will have to be at least 2 V or more. Nothing will happen if your source is, for example, 1 V. Also, ALL voltage sources have some amount of internal impedance, so ideally, you need something a little bit more than 2 V to light up a 2 V LED.

With that, the voltage that needs to be “dropped” by the “current limiting resistor” needs to be

(Voltage of Source)-(FWD Voltage drop of LED)/Current.

So, at 9 V supply, and 2V drop across LED with 20 mA current flow, you get
= 350 ohms


Ok I will use coin cell then adjust,
Ok thanks @Anool

Means I use extra 9v
To light up led
And it is difused :rofl:

You mean the LED fused?