Inductors: Inductors are another type of electronic device that can block DC and pass AC. They consist of a coil of wire. When a DC voltage is applied to an inductor, the current flowing through the coil creates a magnetic field. This magnetic field opposes any change in current, effectively blocking DC current. However, when an AC voltage is applied, the alternating current causes the magnetic field to expand and collapse, allowing the AC current to flow.
Transformers: Transformers are electrical devices that use the principles of electromagnetic induction to transfer electrical energy from one circuit to another. They consist of two coils of wire, a primary coil and a secondary coil, wound around a common iron core. When an AC voltage is applied to the primary coil, it creates a changing magnetic field in the core. This changing magnetic field induces an AC voltage in the secondary coil. The ratio of the number of turns in the primary coil to the number of turns in the secondary coil determines the voltage gain or loss of the transformer. Transformers can be used to block DC and pass AC because DC current does not produce a changing magnetic field, so it is not transferred to the secondary coil.
These are some of the common devices that can be used to block DC and pass AC. Each device has its own unique characteristics and applications.