The circuits. To produce any output voltage, an external feedback resistors can be added. The sLM2576 is a Switching Regulator that can produce 15, 12, 5, 0r 3.3V output voltage from maximum supply voltage of 60V or 40V. This LM2476 featured with voltage reference, switch and feedback path for use in either the negative boost or the buck saturation voltage of The LM2576 switch is typically 1.4V. A heatsink may be needed to solve the power dissipation, however the thermal dissipation is internally limited. The LM2576 has quiescent current of 50 µA in standby (on/off high). This circuit is a testing circuit for LM276. Here is the schematic diagram of the circuit:

LM2576 Switching Regulator circuit schematic

The electrolytic capacitors at output and input should be connected with leads as close as possible. The power dissipation must be small because the load is 100R, so the heat sink is not needed. The capacitor’s voltage must higher than the voltages used in the experiment. This circuit uses 40V, 1A Schottky diode or the 40V, 3A 1N5822 for heavier currents.