Pictured above is a standard circuit design for controlling a spot welder for use in building battery packs and other applications. The welder is 12VDC powered from a large battery, and the 555 timer circuit controls the duration of the brief (sub one second) pulse of high current required to perform the spot welds.

We sell a selection of programmable timers with displays which are much simpler to use and set up than a 555 timer circuit with just a potentiometer used to set the current pulse duration. One of these user programmable options is our dual pulse welder timer controller:  http://www.reuk.co.uk/wordpress/dual-pulse-spot-welder-timer-controller/ . A dual pulse when spot welding gives much better results, but requires a complicated circuit and many components to achieve using a 555 timer.

Therefore we put together the following controller which can work with the output side of a standard 555 spot welding circuit to give much better control and dual pulse capability for customers who already have an array of power MOSFETS set up to supply current to their 12V welding apparatus.

The duration of the first pulse, pause, and second pulse can each be set by the user from 0.01 to 1.99 seconds duration with 0.01 second resolution facilitating consistent welds which can be reproduced again and again.

If you need any kind of spot welding timer controller, please email neil@reuk.co.uk with details of your requirements.