4700uF, 50v (or higher volt) 4700 uF 4700 micro Farad Electrolytic Capacitor (Cap Code 478). Voltage rating of the capacitor may be higher than what is mentioned here, subject to availability.

Capacitor Basics

Capacitor is one of the most fundamental passive components with 2 pins. Almost every circuit has one or more capacitors. Capacitors are used in Electronic Circuits to store electrical energy for a short period of time. It is just like RAM or Main Memory in a computer system. Capacitors are used to store and supply little electrical charges momentarily. Farad is the unit of capacitance which signifies how much electrical charge the capacitor can hold at once. The higher the rating, the more charge holding capacity is. Farad is a very large unit of capacitance, usually way too much than an ordinary electrical circuit needs. So, the widely available capacitors have a capacitance ranging from few pico farads (10 to the power -12) to few milifarads (one thousandth).

Types of Capacitors

There are various types of capacitors available in the market. Each of them are specially crafted to service certain way of storing and supplying current. The broadest distinction is based on the type of current the capacitor can be charged with.

Electrolytic Capacitors - Specifically meant for DC Current. These types of capacitors are also called polarized capacitors. One of the 2 pins of these capacitors are +ve terminal and the other is negative terminal. These capacitors are often cylindrical is share and larger in size. These capacitors have their negative terminal denoted and the terminal is smaller than the positive one.

Ceramic Capacitors - These are apolarized capacitors with the capability to work with both DC and AC Currents. Unlike the Electrolytic capacitors, these caps do not have distinct positive and negative terminals, thus they can be attached to a circuit either way. Ceramic capacitors are often very small in size and of disc-shape. Their capability to store charge is usually very small - in the range of pico farads and nano farads.

Polyester Capacitors - These capacitors are similar to Ceramic Capacitors - apolarized and works fine with both AC and DC Current. Unlike Ceramic Capacitors these capacitors are larger in size and has greater tolerance to higher voltage and higher capacity of holding charge, typically in the range of few nano farads to few micro farads.