🧠 1. What is a Resistor? (Quick Reminder)

A resistor is a component that slows down the flow of electric current. It doesn’t stop it, but it resists it.More resistance = less current flows.Less resistance = more current flows.

Now, let’s combine them in two main ways:

🔗 2. Resistors in Series

Imagine you have one straight pipe, but you add more and more narrow sections one after another.

That’s like resistors in series.

🧩 What happens here?

🔌 Current:

• Same current flows through each resistor.

• Because they are all on one path, electrons have no choice.

• 
  

🔋 Voltage:

• The voltage is shared across the resistors.

• Bigger resistor = bigger share of voltage.

• The total voltage of the battery is split up.

🔬 Formula for total resistance:

Rtotal=R1+R2+R3+…

(Just add the resistances!)

⚡ Example:

• If you connect a 5Ω and a 10Ω resistor in series:

Rtotal=5+10=15

So the circuit becomes harder to flow (more resistance).

🌿 3. Resistors in Parallel

Now imagine instead of one path, you give the water many different pipes to flow through.

That’s like resistors in parallel.

🧩 What happens here?

🔌 Current:

• The current splits up between the resistors.

• The more paths, the easier it is for current to flow.

🔋 Voltage:

• Each resistor gets the same voltage from the battery.

• Because they are all connected directly across the battery.

🔬 Formula for total resistance:

This one's a bit tricky:

1Rtotal=1R1+1R2+1R3+…

Or you can think:

• Total resistance in parallel is always less than the smallest resistor.

⚡ 4. Voltage in Series Circuits

Let’s say you have a battery of 12V and two resistors in series: 4Ω and 8Ω.

The current is the same through both.

To find voltage across each resistor, we use Ohm’s Law:

V=I×R

But first, find total resistance:

R=4+8=12 Ω

So voltage divides across resistors depending on their resistance!

🪙 5. Potential Divider Circuit

Now this is very important in electronics.

A potential divider is just two (or more) resistors in series connected to a voltage supply.

You take the output voltage from between them.

🎯 Why use it?

To get a smaller voltage from a bigger one.

🔬 How it works:

If you have two resistors in series:

• R1on top

• R2 on bottom

• Connected to a battery of voltage Vin

Then the output voltage across R2R_2R2​ is:

Vout=R2R1+R2×Vin

This divides the input voltage depending on the ratio of the resistors.

📦 Summary (in feel-like points):

• Series resistors: one path, current same, resistance adds, voltage splits.

• Parallel resistors: many paths, voltage same, current splits, total resistance goes down.

• Voltage in series: divides based on resistance.

• Potential divider: uses resistor ratios to get a smaller voltage.