Magnetic circuits obey other laws that are similar to electrical circuit laws. The technology relies on an unstable mechanical configuration that forms part of the electrical circuit. Another use is for delaying the closing or opening of an electrical circuit. The mechanical parts act by forming a varying electrical circuit. A switch that is operated by another electrical circuit is called a relay. A generator forces electrons to flow through an external electrical circuit. The circuit functions as if the nodes were physically connected as with an electrical circuit. The way this works is by completing an electrical circuit to create an electrical arc. Radio emissions generated by a fixed electrical circuit are usually polarized, producing anisotropic radiation. However, it is not strongly so and coupling to the electrical circuit is weak. A wiring diagram is a simplified conventional pictorial representation of an electrical circuit. In 1812 Russian engineer Pavel Shilling exploded an underwater mine using an electrical circuit. An electrical circuit requires at least two conductors. More recently, they sustained themselves by the manufacture of electrical circuit breakers and other products. Another type of electrical circuit is an "active" low-pass filter.