Hierarchy classification:

1. top of the aat hierarchies
2. Objects Facet
3. Furnishings and Equipment (hierarchy name)
4. Tools and Equipment (hierarchy name)
5. equipment
6. [equipment by process]
7. amplifiers

Anotations

Scope note:

Amplifiers in which small electrical currents and voltages are amplified before they can operate devices, where the current flows in one direction, rather than with alternating current in which the direction of the flow of electrons switches back and forth at regular intervals or cycles.