A potentiometer has 3 contacts and is usually used to control voltage. It can be used like this as a transducer converting position (angle of the control spindle) to an electrical signal.
Resistor A resistor restricts the flow of charge. Uses include limiting the current passing through an LED, and slowly charging a capacitor in a timing circuit. Some publications use the old resistor symbol
Ammeter Measures current.
An AND gate can have two or more inputs. The output of an AND gate is true when all its inputs are true.