The possible advantages and disadvantages of driving cryotron circuits with a low impedance transmission system instead of a high impedance system are discussed. It is shown that although losses are higher in a low impedance cable, a reduction in the signal coupled between cables in a cryotron system is possible when low impedance cable is used. Two low impedance generators are described. These generators have a maximum frequency between 500 kc and 1 Mc. The rise time is less than 2 nsec and can be improved when the generators are packaged in strip line module form. Pulse amplitude is about 1.5 A. Pulse width is variable by use of a delay cable. © 1962 The American Institute of Physics.