Added amplifier calculation

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2023-02-23 00:48:30 +04:00
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@@ -38,12 +38,41 @@ The program generates inverted pulses, since there will be a transistor switch a
A transistor switch is used as a power amplifier in this work. I used a soviet NPN transistor KT603V (КТ603В).
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### Initial data
- $I_{c.sat} = 150\ mA$ - collector saturation current
- $U_{c.-e.sat} = 0.3\ V$ - collector-emitter voltage in saturation mode
- $E_s = 34\ V$ - external power supply voltage
- $U_{in} = 5\ V$ - voltage at the transistor input
- $\beta = 40$ - transistor gain
- $S = 1.2...1.5$ saturation coefficient. Let's take it equal to 1.5
### Collector resistance
$R_c = \frac{E_s - U_{c.-e.sat}}{I_{c.sat}} = \frac{34 - 0.3}{0.150} = 224.7\ \Omega$
### Base current
$I_b = \frac{I_{c.sat}}{\beta}S = \frac{0.150}{40} \cdot 1.5 = 3.75\ mA$
### Base resistance
$R_b = \frac{U_{in} - 0.7 V}{I_b} = \frac{5 - 0.7}{0.00375} = 1146.7\ \Omega$
It is also necessary to choose the accelerating capacity of the $C_a$ in order for the
pulses to have a sharper front shape. Let's take $C_a = 240\ pF$.
The calculated resistors must be brought to the standard row E24. Thus we get the parameters of the power amplifier:
- $R_c = 240\ \Omega$
- $R_b = 1.1\ k\Omega$
- $C_a = 240\ pF$
## Results
Using an oscilloscope, we can estimate the characteristics of the pulses.
### Without amplifier
![](images/without_amp.png)