TE 93 is a microprocessor welding control unit for single-phase resistance welders. The welding control unit is used to control the welder parts and, in particular, the thyristors adjusting the welding current. The peculiar feature which characterises the control unit TE 93 is that it can be used in combination with other control units of the same type in order to perform welding sequences. The working cycle carried out by the TE 93 is described through 12 programming parameters. The TE 93 can be used for both manual and pneumatic-operated welders.