A tilt fuze or fuse is a device usually used in the operation of car bomb

Car bomb

A car bomb, or truck bomb also known as a Vehicle Borne Improvised Explosive Device , is an improvised explosive device placed in a car or other vehicle and then detonated. It is commonly used as a weapon of assassination, terrorism, or guerrilla warfare, to kill the occupants of the vehicle,...

s and other such detonator

Detonator

A detonator is a device used to trigger an explosive device. Detonators can be chemically, mechanically, or electrically initiated, the latter two being the most common....

s, relying on the force of a jerk or similar movement for the triggering of the desired explosion.

The tilt fuze is typically a home-made mercury switch

Mercury switch

A mercury switch is a switch whose purpose is to allow or interrupt the flow of electric current in an electrical circuit in a manner that is dependent on the switch's physical position or alignment relative to the direction of the "pull" of earth's gravity, or other inertia.Mercury switches...

. It consists of a small tube no larger than a medical tablet bottle, made from plastic, glass or some other such material. At the bottom end of the tube, a certain volume of mercury

Mercury (element)

Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...

 is placed, while at the cap end are wired two live

Live wire (electricity)

The live wire in an AC electrical circuit refers to the wire which carries an oscillating voltage with respect to the earth...

 electrical contacts linked to a battery and bomb. Once this apparatus has been erected, the tilt fuze is affixed to or placed in the target vehicle; most usually, the tube is attached to the underside of the vehicle, below the driver or passenger's seat (depending on the desired target and the strength and quantity of the detonators) or within the mudguards.

The function of the fuze is such that when it is tilted or moved, the mercury – a liquid metal – will slide down the tube and close the electrical circuit

Electronic circuit

An electronic circuit is composed of individual electronic components, such as resistors, transistors, capacitors, inductors and diodes, connected by conductive wires or traces through which electric current can flow...

 wired to the bomb. Once the circuit is closed, the electric current

Electric current

Electric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...

 will then be able to bridge the previously open gap and activate the bomb presumably concealed in another part of the vehicle. Such a tilting of the tilt fuze will likely occur over the regular bumps and jerks of the vehicle driving, ascension up the slope of a hill, or the depression of the brake or acceleration pedals, depending on the placement of the tube.

Due to the volatility in the conduction of the operation, bombers often take precautionary measures to prevent accidental tilting of the fuze while they are setting up. These often include a timer incorporated with the electric current; the bomber may set a certain time period before the contacts become live, therefore ensuring that the bomb cannot be activated until the bomber is well clear of the area.

Tilt fuzes sometimes meet use with the anti-handling device

Anti-handling device

An anti-handling device is an attachment to or integral part of a landmine or other munition e.g. some fuze types found in air-dropped bombs such as the M83, cluster bombs and sea mines. It is specifically designed to prevent tampering. When the protected device is disturbed it detonates, killing...

s incorporated into munitions such as the VS-50 mine

VS-50 mine

The VS-50 is a circular plastic cased anti-personnel blast mine, formerly manufactured by the now-defunct Valsella Meccanotecnica SpA, an Italian high-tech defense industry specialized in area denial systems which was also the manufacturer of the Valmara 69 and one of the first industries in the...

. The Luftwaffe

Luftwaffe

Luftwaffe is a generic German term for an air force. It is also the official name for two of the four historic German air forces, the Wehrmacht air arm founded in 1935 and disbanded in 1946; and the current Bundeswehr air arm founded in 1956....

 in World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

 are known to have made use of variants of the tilt fuze in their bomb fuzes. Tilt fuzes have been used extensively by the Irish Republican Army

Irish Republican Army

The Irish Republican Army was an Irish republican revolutionary military organisation. It was descended from the Irish Volunteers, an organisation established on 25 November 1913 that staged the Easter Rising in April 1916...

 and Irish National Liberation Army

Irish National Liberation Army

The Irish National Liberation Army or INLA is an Irish republican socialist paramilitary group that was formed on 8 December 1974. Its goal is to remove Northern Ireland from the United Kingdom and create a socialist united Ireland....

since 1979.