Making a Simple 1.25 to 35v Variable Power Supply Circuit Using IC LM338

The LM138 series of variable 3-terminal positive voltage regulators is capable of supplying more than 5A over a 1.2V to 32V output range.
They are surely particularly easy to utilize and need just 2 resistors to make the output voltage. Mindful circuit theme has led to outstanding load and line regulation—comparable to a number of commercial power supplies.

The LM138 range comes in a conventional 3-lead transistor package. A unique feature of the LM138 family is time-dependent current restricting.

The current constrain circuitry enables highest currents of up to 12A to be sucked from the regulator for quicker time frames.

This permits the LM138 to be used with excessive transient loads and accelerates start-up under full-load setting.

Under repeated loading situations, the current limit reduces to a harmless value safeguarding the regulator. Furthermore featured on the chip are thermal overload safeguard and safe space coverage for the power transistor.

Overload resistance continues practical despite that the adjustment pin is accidentally turned off. Ordinarily, no capacitors come together unless the unit is situated greater than 6 inches from the input filter capacitors in which instance an input skip over is used. An output capacitor may be combined with build up transient response, when bypassing the adjust

'

 

                                                                          Courtesy: http://www.ti.com/lit/ds/symlink/lm138.pdf