Here we will see how we can make a simple 20 amp 24V adjustable power supply circuit using an LM317 IC and afew 2N3055 transistors configured in their emitter follower mode.
This circuit is quite popular among vehicles or busses in which the batteries offer 24V including different things within the electrical circuit where 12V may be essential. Although a lot of installers make use of a cable through the association of the pair of batteries to obtain 12V which means a lot of wire, and this is not really advised because this impacts on the proper efficiency of the accumulators and also causes discharging of the battery more along with all the accompanying issues that this may result in.
As evident, this 20 Amp adjustable power supply circuit is actually simply an adjustable integrated voltage regulator which can be seen engaged on several parallel power transistors. These transistors carry out the major function as may be witnessed while the regulator IC simply manages maintaining these correctly. Where it is shown as the 24v connector could be the input through the batteries. The indicated 12v connection may be the output and the Gnd connection needs to be grounded. Needless to say, all components (transistors and integrated) should be mounted on a large heatsink for facilitating good heat dissipation as well as must be electrically isolated from the heatsink metal.
Position the 10K preset at the maximum go (or open the 10K preet connection) and hook up to the converter output lamp 12V / 50W. On the output access, link-up the batteries in series with what may be accomplished as 24V. At the output side, parallel to the lamp, attach a continuous scale tester having a appropriate rating (about 50V). Now begin to turn the preset so that the lamp lights and the tester shows 12V...that's all, your 20 amp 24V power supply circuit is set and ready to be used