The paper describes a new and simple voltage-stabilizing circuit which is inherently capable of adjustment for infinite stabilization ratio and zero output resistance; the circuit is suitable for outputs of from 70 volts upwards, but has particular advantages for voltages of the order of 1–15 kV. The principle of operation is discussed, and the conditions necessary for optimum performance are investigated. Details of a practical circuit are given, and the performance limitations imposed by non-linearity of valve characteristics are dealt with in an Appendix.