| 摘要 |
An electronic d.c. telegraph transmitter comprises a transmitting keying circuit and a current regulating circuit which operates in accordance with the principle of a continuous regulator and serves to maintain the line current constant. The power loss which is converted into heat is as small as possible. Between the current regulating circuit and the telegraph battery, a switching stage connects only one tap of the telegraph battery to the input of the current regulating circuit. The voltage present at the input of the current regulating circuit is automatically increased or reduced in stepped fashion in dependence upon the transmitting voltage which occurs on the transmission line. |
