Can you use a rheostat to lower voltage?

Yes, a rheostat can be used to lower voltage in a circuit by increasing resistance, which in turn reduces the current flowing through it according to Ohm's Law (V = IR). By adjusting the resistance, the voltage drop across the rheostat increases, effectively lowering the voltage available to the load connected in the circuit. However, rheostats are typically less efficient and can generate heat, so they are often replaced with more efficient electronic methods for voltage regulation in modern applications.