A diode is a lossy passive electronic component, whereas a capacitor is a non-lossy passive electronic component. A diode is a type of electrical device that conducts the current only in one direction. The direction is defined from anode to cathode. In other words, it is the simplest of the two terminal unilateral semiconductor devices.
A diode behaves like a capacitor when its voltage is less than the forward voltage specification, i.e., when it's turned off. What is its usual capacitance when the diode (zener) is turned off is a common question. A diode is made when P-doped material and N-doped material are put side by side.
Additionally, diodes are often used to protect circuits from voltage spikes, like in the case of light-emitting diodes (LEDs). Capacitors, meanwhile, can be found in applications ranging from tuning radios to managing power surges in power grids. Allows current to flow in one direction only. Stores and releases electrical energy.
Electrical Diodes: What is Diode? Electrical Diodes are semiconductor devices that allow current to flow in only one direction. They consist of a PN junction, created by combining P-type and N-type semiconductor materials. Enable the flow of current in one direction (forward-biased) while blocking it in the opposite direction (reverse-biased).
BUT (and its a big BUT) at DC (direct current) the capacitor is an OPEN CIRCUIT. So connecting a capacitor from a point in the circuit to ground it effectively short circuits the AC component but does not alter the DC value. A diode only allows current to flow in one direction and changes AC into DC.
A Diode is a two-terminal electronic component that allows the flow of current only in one direction. If a diode is installed in the other way round i.e. in the reverse direction, this will block the flow of current. The diode is therefore a polarized component. It has the + and – sides which are often called the Anode (+) and the cathode (-).