Can a Boolean circuit by itself be considered an algorithm (a single step algorithm if you like)? For instance say you have a simple tree circuit with two AND gates as the input gates feeding a single OR gate for a depth two circuit. Now change the AND gates to XOR gates, is it correct to say that I now have a different algorithm for any given input? 
Can a Boolean circuit be considered an algorithm?
algorithms;terminology;circuits
Look at the formal definition of algorithm:Algorithms works in discrete time, (step by step), defining computational states for each input.Algorithms must be independent of its implementation, and each state must be formally described using first-order structures.Transitions from one state to another must take a finite and fixed number of terms in the current state.Circuits works naturally in this way, so you can make an algorithm from here using high-level descriptions (flow charts, pseudocode) or formal descriptions and of course the implementation will be a circuit.