When the light open and close at night, it is always
bringing uncomfortable felling due to the light suddenly turned bright
or dark. So we will introduce an easy and economic way for you to make a fade in and out on-off in your bedroom, it
can effectively eliminate uncomfortable felling from the light suddenly
changes, makes your bedroom fashionable colorful and full of warmth.
What is the theory?
The circuit of the light switch is shown in below figure. The light
switch controller is consists of transistor VT1, VT2 and resistor-capacitor
unit. Because VT1 and VT2 must be work in DC condition, so we can use another
four crystal diode VD1-VD4 to constitute a bridge rectifier, in order to transform
200V AC to pulse full- wave DC power supplies. SA is the light hand switch, H
is an hypothetical bulb for convenience explain.
Preparation
of components
There
are a total of 12 components in this Making (including blub and switch), BOM
list in below table.
BOM
List
|
Label
|
Name
|
Type
and specification
|
Quantity
|
|
VT1
|
Triode
transistor
|
3DA87E,
amplification factor β＞50
|
1
|
|
VT2
|
Triode
transistor
|
BU406,
amplification factor β＞120
|
1
|
|
VD1~VD4
|
Crystal
diode
|
1N4004
|
4
|
|
R1,R2
|
Carbon-film
Resistor
|
RTX-1/4W,
680kΩ
|
2
|
|
R3
|
Metal
film resistor
|
RJ-1W,
75kΩ
|
1
|
|
C
|
Electrolytic
condenser
|
CD11M-160V,
47μF
|
1
|
|
H
|
Bulb
|
KW≤100W
|
1
|
|
SA
|
On-off
control
|
General-use
hand switch control
|
1
|
Handmade
and use
We
can use a knife to cut away useless copper on the FR-4 material board, finish
board is shown at the following picture.
Don't
know how to cut away?
Step
1, Cut off a board Size 40mm*30mm, Metal ruler and knife/ hacksaw is ok
Step
2, Draw the circuit in the board, Paint pen is ok
Step
3, Cut away the useless copper carefully
Step
4, Drill holes, Mini electric drill or bench drill is ok
Step
5, Soldering
Step
6, Install the PCB into your mounting box and connecting line according to the following
picture.
That's
it!
Any question, please feel free to contact
us.
