A resistor affects current in a circuit by limiting its flow according to Ohm’s law, V = IR, where V is voltage, I is current, and R is resistance. When current passes through a resistor, it experiences a voltage drop proportional to the current flowing through it and the resistance value. Therefore, while a resistor doesn’t reduce current in an absolute sense, it limits the amount of current that can flow through it based on its resistance value.
Voltage does drop across a resistor when current flows through it. This voltage drop is directly proportional to the current passing through the resistor and its resistance. For example, if a resistor has a resistance of 10 ohms and a current of 1 ampere flows through it, the voltage drop across the resistor will be 10 volts (V = IR = 1A * 10Ω = 10V).
In a circuit, as resistance increases, assuming the voltage source remains constant, the current flowing through the circuit decreases. This relationship is described by Ohm’s law, where higher resistance leads to lower current for a given voltage. Therefore, while resistance itself doesn’t directly decrease voltage, it affects the current flow, which in turn influences voltage drop across components in the circuit.
When resistors are connected in series in a circuit, the total resistance increases, and according to Ohm’s law, the total current decreases for a given voltage. Each resistor in a series circuit contributes to the overall resistance, thereby reducing the total current flowing through the circuit. This property is utilized in various applications to control current levels and protect components from excessive current.
Resistors do not subtract voltage in the conventional sense. Instead, they cause a voltage drop proportional to the current passing through them and their resistance value. This voltage drop represents the energy dissipated as heat within the resistor due to the flow of electrical current. Therefore, in a circuit, resistors contribute to voltage drops across specific points based on their individual resistance values and the amount of current flowing through them.