2.3.1.2. PRESSURE RELEASE
A pressure release switch can be a stand-alone primary firing switch in a VOIED that is designed to target a normally safe action, such as picking something up. It can also be incorporated as a secondary firing switch in an IED to target poor disposal procedures, such as manually picking up the main charges. They normally incorporate a switch held in an open position, with separated electrical contacts that are trying to close due to the compression of a spring. When a weight is removed the spring is released, the electrical contacts close and the IED functions.
Detonating cord booster
Main charge
Electric detonator
Power source
Separated electrical contacts under pressure
Image 7. Image of a pressure release switch built into the bottom of a main charge
2.3.1.3. TENSION (PULL) VOIED
This is a VOIED that uses the contact of a victim to generate tension – it is also sometimes referred to as a pull IED. Tension VOIED switches can be very simple, such as bare wire loops that are pulled together or insulators that are pulled out from a clothes peg-type mechanism that has been adapted by incorporating electrical contacts. Other electrical components, such as motorcycle brake light switches and micro switches, have also been incorporated into these types of IEDs. Non-electrical IEDs incorporating cocked strikers that release when a pin is pulled out have been encountered.
The following example is a tripwire (tension) VOIED that is intended to function when a lightly armoured vehicle moves through a vulnerable point.
IED tactics
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