SOLUNDA ELECTRONICS
MLELE-KATAVI- TANZANIA
TEL.
+255 763 885 427,
https://solundamediagroup.blogspot.com
POWER AMPLIFIER
PROJECT
First, we need
to know how to make or build transformer? To build a transformer we need to
know where we are going to use the transformer. How many Voltage, Watts and
ampere need? Before all, we must know about the wire gauge and ampere
How many
transistors we have to use on amplifier?
We know that one
transistor can take maximum 1.2 amperes. If we use 15 amperes, so 15/1.2= 12.5.
It means in this amplifier, we need minimum 12 transistors. We use this
amplifier 12 transistor board but if you can, please use some extra transistor
for better performance. Using some extra transistor will help to protect the
load and also will be little hot. So we can understand that always we have to
use the transistor according to our transformer. For an example, we are going
to make 500 Watts amplifier. We have to use 50 voltage and 10 amperes.
50X10=500Watts. Like this for 200Watts, 35×6=210Watts. We also have to know
that we can use 30 voltage to 70 voltage. For 2 transistor use 30 voltage and 3
amperes. For 4 transistor use 35 voltage and 5 amperes. For 8 transistor use 40
voltage and 12 amperes. For 12 transistor use 45 voltage and 15 amperes.
Choosing
transformer for power amplifier:
If we used
2sa1943 and 2sc5200 transistors, we have to know that transistor can’t give us
the Watts. The transformer is the main and important subject for making a good
quality amplifier. We know that Voltage X ampere = Watts. According
to the rules 45X15=675Watts. So this transformer can give us 675Watts.So we can
understand that we use the transformer according to our needs, if we need
1000Watts, we have to use 50X20=1000Watts.
How many
voltages and amperes need for 2 transistor circuit board?
If we use 2 transistors
in this circuit, one being 2sa1943 and another being 2sc5200. How many voltages
and amperes we have to use? We know one transistor can take maximum 1.2 amperes
so here in this circuit, we are using 2 transistors. Since we know that Voltage X Ampere = Watts. Then 1.2X2=2.4.
So we can use 2.4 amperes in this circuit. How many Watts can we get from this
circuit? We can use 2.4 amperes. If we use 35-0-35 Voltage and 2.5-ampere
transformer then we can get Voltage X ampere= Watts, So 35X2.5= 87.5 Watts.
Please remember that always use original or good quality one transistor.
How to know
about original transistor?
There have many groups of the transistor in
our market. For an example, 2sa5200 is the transistor number, and there also
have another number, that is the Group number it starts from 120 to up 900++.
Please always try to use up to 500++ Group number of the transistor.
How to make
transistor audio amplifier.
Here we can see
2 transistors. We can see the different group number. One is 120 and another
one is 728. The 120 number is the low category transistor but the good quality
transistor is up to 500. Here we can see 728 it’s the good one.
ü NB: transformer is important for the amplifier and all transistor
amplifier need center tap transformer i.e. positive, negative and ground
voltage.
ü Alternative transistor
A1943
——-A940
C2073——-C5200
BD136——A940
A614——-A940
BD135—–C2073
BD135—–C2073
BD135——C2073
Building or
constructing transformer
Wire gauge for
transformer
For an example, let’s
go to make a transformer of 1000Watts
amplifier.
For 1000Watts we
need a 1000Watts transformer. First let’s go to make a 1000Watts transformer. If
you don’t know how to make transformer do not worry.
Transformer has
two part, primary part where current enter and secondary part as an output.
For Primary Binding: our
primary voltage is 220v AC. We know that Watts/Voltage=Amperes. So, 1000/220=4.5.
Our primary ampere will be 4.5, so we have to use 4.5-ampere wire. Let’s go to
know which wire can give 4.5 amperes on the table below. So our wire will be 16
or 17 as you want number 16 is for 5.2 amperes and number 17 is for 4.1 ampere
For Secondary binding. Our
amplifier is 1000 watts. We know Watts / Voltage = Ampere. Since the chosen
voltage output of our transformer is 50v…0…50v then, 1000watts/50volts=20Amperes.
We can see in the ampere chart that Gauge number 10 is for 20 amperes. So we
have to use 10 gauge number wire.
Gauge
|
7
|
8
|
9
|
10
|
11
|
12
|
13
|
14
|
15
|
16
|
17
|
18
|
19
|
20
|
21
|
22
|
23
|
24
|
25
|
26
|
27
|
28
|
29
|
30
|
Ampere
|
44.2
|
33.3
|
26.5
|
21.2
|
16.6
|
13.5
|
10.5
|
8.3
|
6.6
|
5.2
|
4.1
|
3.2
|
2.6
|
2
|
1.6
|
1.2
|
1
|
0.8
|
0.6
|
0.5
|
0.4
|
0.3
|
0.29
|
0.22
|
How do you make
a step up transformer?
We can use 12
voltage battery to our 1000 Watts amplifier. Normally we cannot use Battery to
our amplifier because our amplifier starts from 35-0-35 voltage. We use a step
up transformer to increase the voltage. Step up transformer and step down
transformer making rules are the same. For an example, your bobbin is 4X4=16cm.
we know that transformer calculation rule is 42. So 42/16=2.6 turn needed for 1
voltage, so we need 12-0-12 volt. 2.6X12=31.2 turn need in double. For the
secondary we already count that for 1 volt need 2.6 turns so, we need 40-0-40
voltage. 2.6X40=104 turn need in double.
See you next
time………………………………………………
By
BSc. Sosthenes Festo Bigenda
To be continued……………………………..
