So if an amplifier is an electronic circuit(/device) that boosts the voltage and/or power of an AC electrical signal, what do you call such a device that decrease the voltage without increasing the current or better yet reduces the power of an electrical signal?
What I'm thinking of is essentially an amplifier with a voltage or power gain less than unity(in terms of magnitude).
Such a device might be used at a power substation to reduce both the voltage and current from a HV power source. Or when measuring a very high voltage current or signal(with high wattage) by means of a computer where the signal carries enough power to fry the low-power components. As step-down transformer reduces the voltage but increases the current, so I'm not talking about those.