LM317 Variable Output (1.2-17V) Regulator

Variable output regulator is valuable for your test bench tools. This regulator produce variable voltage source from 1.2 to 17Volts. Series type regulator consist of something equivalent to variable-resistance device, an LM317 for this case.

Since series-pass regulator dissipates power and turn it into heat to stabilize the output, this regulator need large heatsink.  The hardest power dissipation occurs at maximum load current at lowest output voltage, and can be expressed as (Vin-Vout)I, and would be equal to (24V-1.2V)1.5A or 34 Watts. make sure you have enough heatsink for this.