Although this example is 5V, there are also 3.3V, 12V, 15V, and adjustable output versions of the LM2576 (see attached datasheet).
The board layout here is using a simple Vero Board which are available from just about any electronics store
Except for the Adjustable output version the same layout can be used for each.
Note: Pin 5 (which is grounded below) can also be used to switch the external loads on/off via a logic input e.g. 0v or 5V, for example an LPT port.
The boards below where built for projects in the Air-Stream Wireless Network as the circuit is ideal for Power over Ethernet (PoE) applications where a Wireless Access Point is mounted up on the mast.