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POWER SUPPLY

MODEL XP-720

Instruction Manual

Elenco Electronics, Inc.

Copyright © 1997 Elenco Electronics, Inc.

Revised 2000      REV-A                                                 753270

Summary of Contents for XP-720

Page 1: ...POWER SUPPLY MODEL XP 720 Instruction Manual Elenco Electronics Inc Copyright 1997 Elenco Electronics Inc Revised 2000 REV A 753270 ...

Page 2: ...ltage setting due to the special regulation circuit 4 Connect the positive lead of your equipment to the red output terminal and the negative lead to the black terminal when using the positive supplies For the negative voltage use the yellow terminal 5 Care must be taken not to exceed the current reading as the supplies will turn themselves off if overheated 6 The Model XP 720 has an added feature...

Page 3: ...and 2B Diodes are semiconductor devices that allow current to flow in one direction The arrow in Figure 3 points to the direction that the current will flow Only when the transformer voltage is positive will current flow through the diodes Figure 3 shows the simplest possible rectifier circuit This circuit is known as a half wave rectifier Here the diode conducts only half of the time when the AC ...

Page 4: ...pass transistor It controls the current reaching the output Transistors Q3 and Q4 are emitter followers Their function is to raise the impedance of the pass transistor Note that transistors Q2 Q3 Q4 and Q5 and resistor R1 form a close loop Also note that the feedback to the base of Q2 is negative that is when the base of Q2 goes positive the output at emitter Q5 goes negative Now if the 2V output ...

Page 5: ...e LM 7805 IC will overheat turning itself off and thus limiting the circuit at about 2 6A The first 2A of current is drawn by the LM 7805 IC The next 3A are drawn by transistor Q2 Thereafter the current is drawn by the LM 7805 IC until it overheats and turns itself off This is a very effective circuit capable of regulating the output voltage at a constant 5 volts and yet delivering over 3A of curr...

Page 6: ...ssis 612012 1 Heat Sink 615010 2 Knob 622009 QTY DESCRIPTION PART 1 Strain Relief 624003 5 Bushing 624007 4 PC Board Stand off 625002 2 Black Binding Post 625031 7 Lockwasher 625031LW 7 Nut 625031HN 2 Red Binding Post 625032 3 Yellow Binding Post 625034 3 Cable Ties 628982 5 Screw 6 32 x 3 8 641640 2 Screw 8 32 x 3 8 641840 4 Screw 6 x 3 8 black 642652 2 Screw 6 x 3 8 black 642660 2 Nut 7mm 644101...

Page 7: ... 6 SCHEMATIC DIAGRAM ...

Page 8: ...Elenco Electronics Inc 150 W Carpenter Avenue Wheeling IL 60090 847 541 3800 http www elenco com e mail elenco elenco com ...

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