Integrated Circuits
LM317T 1A variable regulator
U1
LM337T 1A variable regulator
U2
Ensure that both devices are TO-220 types and not any surface mounting or TO-3 packages. I
much prefer the devices that are made by National Semiconductor. They are available from
other manufacturers but National's devices have a thicker and more rigid heatsink tab.
Do not fit solder these into the board just yet. They are only to be soldered once the board is
fitted to the panel. See the section on mounting the PSU2 board later in this document.
Discrete Semiconductors
1N4004 rectifier diode
D4, D5, D6, D9, D11
1N5819 Schottky diode
D3, D10
1N5401 rectifier diode
D1, D2, D7, D8
For 1N4004 you can use any other 1N400X part such as 1N4001, 1N4002, etc.
D2 and D8 do not need to be fitted if you are using a single phase wall wart or line lump.
5mm green LED
-15V
5mm red or orange LED
+15V
LED cathodes are denoted by the square pad on the PCB. LEDs will not light up if fitted the
wrong way.
The component marked as LED is the optional front panel power on or standby indicator.
This LED connected to the board via wires and is not fitted to the board.
5mm red LED
LED
Trimmer
500R multiturn (eg. Bourns 3296W)
ADJ+, ADJ-
Miscellaneous
20mm fuseholder PC mount
F1, F2
Antisurge 20mm fuse
F1, F2
For current rating see page 5
4-way screw terminal 5mm
POWER, SWITCH
TO-220 insulator pad.
U1, U2
Suitable power switch
10