Abstract: Power supply means for a laser flashtube or similar lamp (such as a continuous wave arc lamp) consists of high frequency switch means for providing a pulse train output from a direct current supply with provision for modulating the pulse width of said output and a filter which receives the modulated pulse train output for substantially removing high frequency ripple therefrom prior to passage of the resulting pulse train output to the flashtube or similar lamp. For supplying a simmer current to the flashtube or lamp the modulated pulse train output may be raised to a DC level for this purpose. The high frequency switch means may consist of at least one transistor or thyristor and the filter may consist of an inductor/capacitor arrangement.