Hello, readers welcome to the new post. Today we will learn Introduction to BC547 Transistor. The transistor is a semiconductor component that has three pins and comes in NPN and PNP configurations. It is used in different circuits as amplifiers and switches. BC547 is NPN configured transistor that also comes in three pins structure emitter, collector, and base.
In this post, we will discuss different parameters for BC547 like structure, pins working, and applications. So let’s get started
Introduction to BC547 Transistor
- BC547 transistor is used in amplifier circuits to amplify the input signal. It uses the small value of current at the base terminal to regulate the high current between the collector and the emitter
- It is mostly preferred for amplifiers and switching circuits.
- It has a gain value from 110 to 800 that defines its amplification range. The highest value of current that can pass through this collector is 100mA so try to avoid a high current.
- For biasing of the transistor current at its base pin is provided and must be less than five milliampere
- If the transistor is in a completely biased state so one hundred milliampere current can pass through the collector and emitter. This phase of the transistor is called the saturation region and the voltage of transistor VCE or base-emitter is about two hundred to nine millivolts.
- If there is no base current provided transistor is in off state and called cut off region of the transistor and base-emitter volts can be 660 millivolts
BC547 Technical specifications
- It has a noise value of about two to ten decibels
- Its operating temperature is about minus sixty-five to one-fifty centigrade
- It has DC current gain is 110 to 800
- The transition frequency for this transistor is three hundred megahertz
- 500 mW is collector dissipation
- VEB is six volts
- VCE is 45 volts
- collector current if forty-five volts
- the highest collector current is one hundred milliamps
- It is NPN configured transistor and To-92 its packaging
| Features | Details |
| Type |
NPN bipolar junction transistor
|
| Maximum Collector Current | 100 mA |
| Collector-Emitter Voltage | 45 V |
| (VCB) | 80 V |
| (VBE) | 6 V |
| (h_FE) |
110 to 800
|
| IB | Up to 5 mA |
|
Pins
|
Pin 1: Collector |
| Pin 2: Base | |
| Pin 3: Emitter | |
|
Working modes
|
Saturation Region 100 mA to flow from collector to emitter, with a typical VCE is 200 mV
|
|
Active Region: work like amplifier to amplify input signals
|
|
|
Cut-off Region: off when the base current is removed, VBE is 660 mV
|
|
|
Applications
|
Amplifies audio and radio frequency signals
|
|
Switching: Controls heavy loads through use of input signals,
|
|
|
Used in motor control
|
BC547 Transistor Equivalent
- The equivalent transistor of BC547 are mentioned below
- BC548, BC549, BC636, BC639, 2N2222 TO-92, 2N2222 TO-18, 2N2369, 2N3055 and 2N3904
2N2222:
- The 2N2222 is an NPN transistor and is used as a replacement for BC547 in different uses. it comes with the same pins and electrical features and has features for handling high-current
S8050:
- The S8050 is NPN transistor also used replacement for BC547. It has the same voltage and current ratings and part of the signal-switching
2N3904:
- The 2N3904 is a low-power NPN transistor used for small signal amplification and some other switching ciruits for on and off circuits. it comes with the same features as BC547 and works with direct use.
C1815:
- The C1815 is also an NPN transistor that handles small signals with low current features as BC547 do. It is part of audio and low-frequency circuits.
MPS2222:
- It is also best for replacing the BC547 transistor and comes with the same features and best for low-power amplifiers and switching circuits.
2N3904 VS BC547
- There is a pin configured at different sequences for both transistors. The pin sequence for 2N3904 is Emitter base and collector and for BC547 is collector, base, and emitter
- VCE for BC547 is 50 volts and for 2n3904 forty volts
- base current 100mA for BC547 are 200mA for 2N3904
- Power dissipation of 2N3904 is 626 mA and 500mA for BC547
- frequency for bC547 is three hundred and others also have the same value
| Ratings and Characteristics | 2N3904 | BC547 |
| Collector-Emitter Voltage (Vceo) | 40V | 50V |
| DC Current Gain (hFE) | 30 To 300 | 110 To 800 |
| Frequency (fT) | 300 MHz | 300 MHz |
| Collector Current (Ic) | 200mA | 100mA |
| Total Device Dissipation (PD) | 625mW | 500mW |
BC547 Transistor Pinout
- It has three pinout collector base and emitter
- Emitter used to get current from the transistor
- The base is a control point like tap here biasing volts are provided
- At the collector current moves toward the inner circuit
BC547 as Switch
- There is a cut-off region and the saturation region are operation region of BC547 as the switch is working.
- The operation of the transistor is an open switch for forward biasing and a closed switch for reverse biasing and for getting the biasing their required current is provided at the base pin.
- Above we discussed that the base current for BC547 is five milliamperes so try to follow this value. A larger current can damage the transistor and must use current limiting resistance with a base pin in a series combination
- TO find the value base resistance use this formula
- Rb= VBE/IB
- VBE must be five volts and the base current can base on the collector current
BC547 as Amplifier
- When BC547 work as amplify it has an active region and helps to amplify power volts and current at different values
- For amplification, some common circuits are used
- Common base amplifier
- Common emitter amplifier
- Common collector amplifier
BC547 Applications
- Common applications are discussed here
- It is used in LED drivers, Relay driver
- High-speed switching circuits
- PWM circuits
- signal amplifiers
- Darlington pairs
Circuit of BC547 Transistor
Here we have made a circuit diagram for the BC547 transistor where it works the switch and performs ON/Off operation. if the cirucit is getting the power it is active and the relay connects in the circuit is in the off state. For this high voltage is given at the base of the Q3 transistor with the use of an R7 resistor and keeps it off.
When switch S2 is open, the transistor Q4 starts operation and helps relay L3 to the latch. The base terminal of the Q3 transistor is pulled at a low voltage level, resulting in L2 LED glowing it means power is not connected.
The transistor Q4 gets on from voltage about collectors terminals of transistor Q3 and gets voltage through resistance through R8.
If switch S1 is pressed, the base of the Q3 transistor is pulled to a high voltage level and as a result deactivates L2. As a result of the base of the Q4 transistor pulled through the R8 resistor relay L3 is turned off.
Working Modes of BC547
- There are two modes of BC547 transistor working that are forward-biased and reverse-biased state. For forward biased mode two points of like emitter and collectors provide current flow.
- The reverse-biased mode does not allow current flow through the circuit and works as an open switch
Can Use 2N3904 Instead of BC547?
- The value of high collector-to-emitter voltage for 2n3904 is 40 volts, and BC547 has a VCEO 50 volts. if we change the transistor collector to emitter voltage is important, a ten-volt difference is not an issue for load getting volts less than 40 volts.
- The high collector current of 2N3904 is 200mA and the collector current of BC547 is 100mA.
- The net dissipation of 2n3904 is 625 mW and BC547 has 500mA. This less change does not affect working.
- If using a transistor for high-frequency circuits, then fT is considered. Since ft value for 300MHA is good both transistors are used for Rf circuits without any issue.
NPN 547 Transistors vs PNP 547 Transistors
| NPN 547 Transistors |
PNP 547 Transistors
|
| It is a very common type for 547-family |
Less commonly used but part of different circuits
|
| Current direction from collector to emitter. If a positive supply at base |
Current direction from emitter to collector in result negative voltage is applied to the base
|
| switching and amplification circuits uses it. |
Part of complementary circuits with NPN transistors
|
| Types are BC547, 2N3904, and 2N2222 |
BC557 and 2N3906
|
BC547 vs 2N3904 vs 2N2222A
| Features | BC547 | 2N3904 | 2N2222A |
|
MAX IC
|
100 mA | 200 mA | 600 mA |
|
MAX Dissipation
|
500 mA | 625 mW | 500 mW |
|
(hFE)
|
110-800 | 30-300 | 35-300 |
|
(VCEO)
|
45 V | 40 V | 40 V |
|
Collector-Base Voltage (VCBO)
|
50 V | 60 V | 75 V |
|
Frequency (fT)
|
300 MHz | 300 MHz | 300 MHz |
FAQ
Why BC547 transistor used?
- In the electrical circuit, BC547 is used as an amplifier and switch. It is also used for logic gates and audio amplifier circuits sine easily handles small loads such as relays.
What is value of BC547 Transistor’s maximum ratings?
- The BC547 has 45 V for collector-emitter volts, 100mA for collector current, and 5mA for base current.
Can BC547 Transistor handle higher volts?
- BC547 has features to handle high collector-emitter volts for 45 volts and it will damaged if the voltage is higher than the rated value.
What current needed to switch on a BC547 Transistor?
- The required current for collectors and current gain for transistors define the base current used for turning on BC547. Such as the need for a 0.1mA base current. If we needed to flow 10mA current through collectors hfe is 100.
Is it good to replaceBC547 Transistor with 2N2222 Transistor?
- Both come with different pins and features, but we can replace them in low-power uses.
What happens if I provide the BC547 Transistor’s base an excessive amount of voltage?
- Overvoltage at the base causes high base-emitter voltage which is about 6 volts. It can break down and damagethe transistor..
That is all about the BC547 Transistor, all details have explained if you have a query ask here
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