hi, thanks for your reply - what would you recommend for using in this specification then if you think an lm350 TO-3 package would not do the trick - i only require a max 20v output from variable supply,
it appears in a lm317 using a SPICE model i found, simulation in multisim shows the circuit to be operating as required, although i haven't looked into current operating stats yet. Voltage operation is as required though. A pointer in the right direction of a voltage regulator of use to me would be great, i will be adding digital led display to this circuit at a later date