Understand it in 60 seconds · Analog
The voltage divider
How a volume knob makes the same song quieter: two resistor sections share the voltage. Follow the 6 V → 3 V → 4 V analogy, move the potentiometer wiper, and see the same wave with a smaller amplitude before it reaches the amplifier.
Beginner · published 3 October 2026
Free · no account needed · it opens in your browser
What you will understand
- Two resistors share the voltage: Vout = Vin · R2 / (R1 + R2), as long as the output draws almost no current.
- A potentiometer is one resistive track split by its wiper: turn it down and R2 shrinks, so less voltage comes out.
- At the ground end: silence. At the input end: the full signal.
- The wave keeps its frequency and its phase; only its amplitude shrinks (R1 = 8 kΩ, R2 = 2 kΩ: 20 % of the voltage).
- The divider feeds an amplifier input, which draws almost no current; a speaker straight on the wiper would load the divider.
Inside the lesson
The cheat sheet
Every equation on one page, with the circuit drawn. Export it to PDF to keep it.
The animated presentation
The idea step by step, with the currents flowing in the circuit. Press Present (F5) to play it.
Your own copy
It opens as a Circuit Notebook project: change the values, reuse the circuit in your report.
Read next
-
Components
The resistor
The resistor in 60 seconds: a water valve that limits current, Ohm’s law, how to protect an LED, and where the energy goes (heat and power rating).
-
Analog
The night pumpkin
Build a pumpkin whose eyes light up in the dark: an LDR, a BC547 transistor and two LEDs on a breadboard. Parts list, schematic, 5 steps, 30 minutes.
