Posted this in the wrond section, so reposting here:

Complete newby to electronics, but have a basic understanding. Have an idea for a little project and tried searching the net and couldn't find a component or its technical term, what I am after is a component that when built into a basic battery operated circuit works as a "release" in that when the circuit is off the (say for instance pencil) is held, but when the circuit is switched on, the component (possibly a claw) opens to release what it is holding. Not sure of its technical term, so having difficulty finding anywhere that stock such an item. I'm only talking about a cheap item, basic device which opens when circuit is switched on, incorperated into a basic circuit powered by a 9v battery.

Thanks in advance! and sorry for the crude nature of the question.

 

a solenoid will have two positions, one (held by the spring) will be "open" and other (when voltage is applied) will be close. It is actually linear actuator with 2 positions. You will not have "speed control", "pressure control", "position control" - it is just a piston set fully left or fully right (or up/down, front/back, however you turn it). You can attach anything on that piston (a claw for e.g.) in order for it to "grab/hold".

Solenoids Catalog - Magnetic Sensor Systems

You can also make a grapple using servo's, steppers and other motors that will give you more precise control (speed, position)

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Also you could look at any of those cheap little DC gearmotors they sell like the Tamiya ones.