Circuit Symbols and the Voltage Divider
Every symbol from the lecture shown as a real component on a bench — knife switch, cartridge fuse, moving-coil meters, ceramic resistor, wound rheostat. Click any one to see the symbol you would draw for it, slide the rheostat to share out the 12 V, and push the current far enough to blow the fuse.
How to use this simulation
- Click any component on the bench to reveal the circuit symbol drawn for it
- Drag the rheostat slider to change R₂ and watch the 12 V redistribute
- Choose a 5 Ω, 10 Ω or 20 Ω fixed resistor to change the division ratio
- Open the switch to break the loop, or drive the current up until the fuse blows
What to look for
- The two voltmeter readings always add up to the 12 V supply
- Turning the rheostat to zero puts the whole supply across the fixed resistor
- The larger of the two resistors always takes the larger share of the voltage
- The ammeter reads the same current whichever point in the series loop it sits at
- The fuse melts at its rated current and the entire loop dies at once, not just one branch
The physics behind it
Two resistors in series carry the same current, so the supply divides between them in proportion to their resistances: V₂ = V·R₂/(R₁ + R₂). Sliding the rheostat changes R₂ and therefore moves that share continuously, which is the whole principle of a potential divider. The fuse is a deliberately weak link whose wire melts once the current exceeds its rating, breaking the circuit before the rest of it is damaged — the current in a series loop being the same everywhere is exactly what makes one fuse able to protect everything.