Ramsey Electronics QAMP20 用户手册
QAMP20 • 8
15. Install Q3 and Q4, 2N3904 NPN transistors, observing proper
orientation of the flat side. These two transistors amplify the signal
diode's output to a level high enough to close relay K1.
orientation of the flat side. These two transistors amplify the signal
diode's output to a level high enough to close relay K1.
16. Install diode D4, 1N4002 style black epoxy diode. Check positioning of
the banded end.
the banded end.
17. Install jumper JMP2. Use a piece of scrap component lead wire bent
into a "staple" shape and inserted into the board like a component.
Jumpers act as electronic "bridges" carrying signals over PC board
circuit traces underneath.
into a "staple" shape and inserted into the board like a component.
Jumpers act as electronic "bridges" carrying signals over PC board
circuit traces underneath.
18. Install C13, .1 µf disc capacitor (marked .1 or 104).
19. Install L4, 10 µH inductor (green body with brown-black-black bands).
20. Install R3, 10 K ohm resistor (brown-black-orange).
21. Install C2, 10 µf electrolytic capacitor. Electrolytic capacitors are
polarized with a ( + ) and a ( - ) lead and must be installed correctly for
proper operation. Generally, capacitors have their ( - ) lead marked
with a black stripe while PC boards have the ( + ) hole indicated.
polarized with a ( + ) and a ( - ) lead and must be installed correctly for
proper operation. Generally, capacitors have their ( - ) lead marked
with a black stripe while PC boards have the ( + ) hole indicated.
22. Install D1, 6.2 volt Zener diode (gray body with a black band). This
diode provides a stable voltage which is used to provide bias for the
power transistors.
diode provides a stable voltage which is used to provide bias for the
power transistors.
23. Install R5, 1 K ohm resistor (brown-black-red).
24. Install R2, 6.8 K ohm resistor (blue-gray-red).
25. Install R1, 1 K ohm resistor (brown-black-red).
26. Locate another 1 K ohm resistor (brown-black-red). Trim back one lead
to a length of ¼ inch. Bend this wire into a small loop as shown. This
loop will act as a convenient point to connect a test probe for setting
the bias voltage. Insert the resistor into the PC board and hold it
carefully while you solder it to the board.
to a length of ¼ inch. Bend this wire into a small loop as shown. This
loop will act as a convenient point to connect a test probe for setting
the bias voltage. Insert the resistor into the PC board and hold it
carefully while you solder it to the board.
27. Install R8, 270 ohm resistor (red-violet-brown).
28. Install C11, .001 µf disc capacitor (marked .001 or 102).
29. Install R9, another 270 ohm resistor (red-violet-brown).
30. Install C12, another .001 µf disc capacitor (marked .001 or 102).
31. Install C8, .1 µf disc capacitor (marked .1 or 104).