Depends on the load on the circuit. This is the basic formula Volt = Current x Load or V=I X R. We assume that the Load is resistive, to get 1 Amp from the 1 Ohm resistance, you need 1 Volt. If you need to pass 1 Amp from a 100 Ohm resistance, applying in the formula V= 1 x 100, you need 100 Volts. The higher the resistive load is, the more Volts you need to get 1 Amp through. There are other factors such as AC and DC currents, and resistive versus resistive + Inductive + Capacitive loads, then complex mathematics apply.
