Use of fastener:
Using screws and bolt help to keep the transistor stay
attached to the heat sink. I used two screws to put it through the transistor.
One screw at the hole at the top of the transistor and the other for the hole
at the bottom of the transistor. The screws would go through the transistor,
the washer, the heat sink and then the securing plate. Once the screws have
gone through, you use nylon lock bolts to secure the screws in place and making
sure that the transistor is in place with the heat sink and is not moving. The transistor collector gives the mounting
screws and bolts electrical conductivity to the other side. The mounting screw
heads are in contact with the transistor so it had electrical conductivity.
To prevent vibration and shaking when you attach a heat sink
to a transistor the washer, screws, bolts and the securing plate will work.
The washer is a thermal conductor but is electrically
insulating so when you attach the transistor (with the washer on it) to the
heat sink, the heat will be transferred from the transistor to the heat sink
with no electric conduction but the use of the transistors conducted parts
(emitter, base and collector), are electrically conducted but it must not get
into contact with the heat sink. The washer’s texture is a bit lumpy so it will
have grip if any vibration and shaking goes on.
The use of the securing plate does what it is named for. The
securing plate holds the transistor and heat sink in place and when it is
attached to the heat sink it is clipped on and would not move from that
position. However, if any vibrations do happen, there is not a guarantee that
it will always stay in place. But the use of the screws and bolts will
definitely guarantee that the heat sink and the transistor will always stay
attached and in place.
The screws go through the top of the transistor and the
bottom of the transistor. It holds the transistor, the washer, the heat sink
and the securing plate in place. The use of the bolts makes sure that there is
extra placement of the transistor to the heat sink. The screws and bolts will
hold all the layers together including the transistor and heat sink together. The
bolts will not move when the vibrations is happening so the heat sink and
transistor will be attached together.
Heat transfer using
The thermal paste/grease is thermally conductive and
electrically insulated meaning that it would not conduct electricity. The
thermal paste will give a good thermal connection between the transistor and
the heat sink. When you are putting the paste on the washer on both sides, it
is vital that the paste does not touch the prong of the transistor as if this
does happen then the prongs would not conduct. When you applying the thermal
paste to to the washer on both sides, you need to make sure that you put enough
on it because it is not good at conducting heat and if too much is applied, it
could cause an increase in thermal resistance. The thermal paste gets rid of
air gaps and spaces so it can maximize heat transfer.