Please feel free to feel ashamed!
Our friend Google could answer most of these questions, but I am in a good mood tonight, so here goes:
Solenoid, A coil of wire, used to create a magnetic field. As a horrid generalisation a solenoid is a single layer coil where the length is greater than the diameter.
Often the term solenoid is used as a short form of solenoid valve. A valve to switch hydraulics or pneumatics which is electrically operated by passing current through a solenoid.
Diode, a device which passes electrical current in one direction only.
A diode has two connections, an anode and a cathode. Conventional current will pass from anode to cathode, but not from cathode to anode.(PS, to all the argumentative types, I know that electrons flow from -ve to +ve, but most of the time I like to think in terms of conventional current which flows from +ve to -ve).
Transistor, amplifies current. At this time on Friday night, that is all I am saying.
Transductor, looks like the Spanish word for Transducer.
Transducer, something which converts energy from one form to another.
Examples:
Microphone, converts sound energy into electrical energy.
Loudspeaker, converts electrical energy into sound energy.
OK?
JimB