This is an unused switching power supply board, you can figure out how to use them, or use them for parts. These were power supplies for vintage Texas Instruments computers, and come directly from the Texas Instruments shipping box, see photos.

The board measures 3-3/4 x 4-3/4 inches. Photo is a representative unit.

1 - TIP31A NPN power transistor, mounted on heatsink
1 - 2N4403 transistor, may have different part number

1 - 1N4934 1A 100V fast recovery rectifier diode

5 - rectifier style diodes

1 - 47uf 10v electrolytic capacitor
2 - 220uf 16v electrolytic capacitors
6 - 330uf 10v electrolytic capacitors
1 - 3,300uf 35v electrolytic capacitor

17 - small axial lead capacitors

1 - toroid coil, 2 windings, 800uH and 1.7mH

12 - resistors

4 - 12uH choke inductor coils

1 - ferrite bead on wire

1 - DPDT switch

1 - 4 position male connector

The seller makes no representation of any item(s) sold to be fit for a particular purpose and assumes no liability for its use or misuse. It is assumed that the unit(s) will be installed and operated by qualified personnel. The purchaser agrees that the seller shall not be held responsible or liable for any injuries or damages, whether incidental or consequential, associated in any way with the item(s).