| 摘要 |
PURPOSE:To obtain an electric power source for terminal drive from a constant voltage circuit while allowing the DC terminal of a circuit to serve as a constant- resistance terminal viewed equivalently from the circuit, by using a combined circuit of a constant-current circuit, constant-voltage circuit and resistor. CONSTITUTION:Constant-current circuit 5-1 is connected in parallel to the series circuit of terminal resistance 5-2 and constant-voltage electric power source 5-3 to form electric power source circuit 5. This circuit 5, when a DC voltage applied between input terminals 4-1 and 4-2 is large enough for the operation of circuits 5-1 and 5-3 or greater than it, becomes equivalent to terminal resistance 5-2 by being viewed from input terminal 4-1 and 4-2 sides. Further, this circuit 5 serves as a resistance and constant-voltage circuit 5-3 can supply constant voltage out. However, the ratio of voltage V0, generated by constant-voltage circuit 5-3, to constant current I0 flowing through constant-current circuit 5-1 should be set equal to resistance value R0 of terminal resistance 5-2. |
