Circuit builder परिपथ निर्माता
Pick a part and tap the board between two dots, or drag it in. Join a cell, a key and a bulb in a loop and switch on. Try series and parallel, add meters, and find out what a fuse is for.
Tap a part to edit it (tap a key twice to switch it). Drag a part to move it.
15 parts on the board. Cell current 0.600 A. A1 reads 0.600 A. V1 reads 3.00 V.
Every part सभी पुर्ज़े
| Part | Value | I (A) | V (V) | P (W) | H (J) | Select |
|---|---|---|---|---|---|---|
| B1 Cell / battery | 3 V | 0.600 | 3.00 | 1.80 | — | |
| K1 Switch (plug key) | closed | 0.600 | 0.00 | — | — | |
| A1 Ammeter | — | 0.600 | 0.00 | — | — | |
| R1 Resistor | 5 Ω | 0.600 | 3.00 | 1.80 | 108.0 | |
| V1 Voltmeter | — | ≈ 0 | 3.00 | — | — |
The physics भौतिकी
Ohm’s law
V = IR. The current through a resistor is proportional to the voltage across it. Double the cell voltage and the ammeter reading doubles.
Series and parallel
In series the same current flows through every part and R = R₁ + R₂ + …. In parallel every branch gets the same voltage and 1/R = 1/R₁ + 1/R₂ + …, so adding branches lowers the total resistance and raises the current.
Power and heating
P = VI = I²R = V²/R, measured in watts. The heat produced in time t is H = I²Rt joules (Joule’s law of heating). A bulb’s brightness here is its power compared with its rating.
The board is solved with modified nodal analysis, the same method circuit simulators use. Wires, keys, fuses and ammeters are ideal (no resistance); voltmeters have 10 MΩ.
Common questions
Why do bulbs in parallel glow brighter than bulbs in series?
In parallel every bulb gets the full voltage of the cell. In series the voltage is shared, so with two identical bulbs each gets half the voltage, a quarter of the power (P = V²/R) and glows much more dimly.
How must an ammeter and a voltmeter be connected?
An ammeter goes in series, so the whole current passes through it; it has almost no resistance. A voltmeter goes in parallel across the part being measured; it has a very high resistance and takes almost no current.
What is a short circuit?
A path of almost zero resistance between the two terminals of a supply. The current becomes very large, wires overheat and can cause a fire. A fuse in series melts and breaks the circuit to prevent this.
Which way does current flow in the circuit?
Conventional current flows from the positive terminal of the cell, through the circuit, to the negative terminal. Electrons actually move the opposite way. The moving dashes on the board show conventional current.
How is the circuit calculated?
With modified nodal analysis: Kirchhoff’s current law is applied at every junction and Ohm’s law for every resistor, and the equations are solved together. It is the same method used by professional circuit simulators.