Electric circuits

• How Does Power Work When Appliances Are Connected in Series?
  In a series circuit, appliances share the supply voltage and carry the same current. Calculate each appliance’s actual power from its resistance.
• How to Calculate the Equivalent Capacitance of an Infinite Ladder
  For an infinite ladder of identical capacitors, self-similarity gives an equivalent capacitance of (√5−1)C/2 for the standard topology.
• How to Calculate the Voltage Across a Resistor
  Calculate voltage across a resistor with Ohm’s law, and learn when a resistor gets the full battery voltage or only part of it.
• How to Measure the EMF of a Cell
  Measure a cell’s EMF with a high-resistance voltmeter for a quick estimate or a potentiometer for a null-balance measurement.
• How Do You Combine Three Resistors in Parallel?
  For three resistors connected across the same two nodes, add their reciprocals, then invert the sum to get the equivalent resistance.
• How Does a Resistor “Know” to Increase the Voltage Across It?
  A resistor does not sense or choose its voltage: the circuit’s source, resistance, current, and electric fields determine the potential difference.
• How Does Electrical Grounding Work?
  Electrical ground can set a circuit's voltage reference or protect against faults. Learn how current returns to its source and when earth matters.
• How Does Resistance Relate Voltage to Current?
  Resistance does not create current; it relates current to voltage. Use Ohm’s law for an ohmic resistor and include the rest of the circuit.
• Why Is Current the Same in a Series Circuit?
  In a steady series circuit, charge conservation makes the current equal through every component; voltage drops differ according to each component’s resistance.
• How Can a Potential Divider Set a Component’s Voltage to Zero?
  A potential divider can set a load’s voltage to zero by placing its wiper at ground; a series variable resistor usually only approaches zero current.
• Does Electricity Take the Path of Least Resistance?
  Electricity does not choose only the least-resistance route. Learn how current divides between branches and how circuit laws determine each path.
• Does a Capacitor Pass DC Current?
  An ideal capacitor carries current while its voltage changes, such as during DC charging, but carries no current after steady state is reached.
• What Is Equivalent Resistance?
  Equivalent resistance is the resistance a single resistor would need to match a network’s voltage–current behavior at specified terminals.
• What Is the Difference Between I²R, V²/R, and VI for Power?
  VI is the general circuit-power formula; I²R and V²/R come from Ohm’s law for a resistor, using its voltage and current.
• What Happens When Different Batteries Are Connected in Parallel?
  Different-voltage batteries in parallel can drive current into each other. Learn how to estimate that current and why mismatched batteries can be unsafe.
• How to Calculate a Voltmeter Reading
  Calculate a voltmeter reading by identifying its connection points, finding the voltage difference between them.