A lead, pronounced like the word "need," is a type of electrical connection. A clip lead is a lead that has a small metal clip on at least one end. This clip allows the lead to temporarily connect to a wire and then easily come loose. This type of lead is generally reusable, so once it is disconnected from one system, it is easy to connect it to another. The connections on a clip lead are usually alligator clips, so clip leads often have local names that stem from the clip’s distinctive name.
As one of the most basic and common forms of electrical connection, leads are quite varied. There are a huge number of different types of leads, ranging from long to short and stiff to flexible. In most cases, a lead’s job is connecting an electrical component to another component or a main system. They also provide physical support, such as stiff leads that move components away from circuit boards. Lastly, some are just simple connections, such as lead wire, for moving current from one place to another.
Leads have many ways of connecting to a system. Many components have two leads, one that connects to a positive terminal and one that connects to a negative. Other, more complex, components may have three or more leads. These usually have a variable output based in the power flowing through them. There are also more simple leads that work similarly to standard wires.
A clip lead is usually a soft wire lead, meaning it does not provide physical support to a component. Most of the time, a clip lead is found on a handheld device since that is one of the few times a component will need constant connection and detachment from a system. These devices are often a means of providing temporary power to a system or as a measurement or diagnostic tool.
When a device using a clip lead provides power, it works like a standard circuit system. Since the device is usually handheld, the power often comes from a battery. The device has two clip leads that connect to a positive and negative terminal on the device to be powered. To prevent shocks, these devices typically have a safety switch so power isn't constantly flowing. Power will flow through the clip lead, into the device and then back out.
Diagnostic and measurement tools may have any number of leads. The diagnostic device will connect to preset locations on the system being checked. As the system runs, it will send information through the leads and into the diagnostic system. The diagnostic device will then translate that into human usable data.