The C945 transistor is an NPN bipolar junction transistor designed for amplification and switching tasks. Engineers and students often choose the c945 for its general-purpose nature, as seen in embedded system simulation tools and educational kits. High import volumes, such as 5,000 units in August 2024, highlight its strong demand in electronics. The c945 offers reliable performance with the following specifications:
| Specification | Value/Description |
|---|---|
| Max Voltage (Vce) | Up to 50V |
| Collector Current | Up to 150mA |
| Current Gain (hFE) | High, ideal for amplifiers |
| Frequency Response | Audio and RF applications |
| Package Type | TO-92 |
Understanding the c945 pinout, datasheet specifications, suitable equivalents, and main applications ensures effective use in electronic circuits.
Key Takeaways
-
The C945 transistor is a reliable NPN device with low noise, high gain, and a low saturation voltage, ideal for audio amplification and switching tasks.
-
Its TO-92 package and clear Emitter-Collector-Base pinout make it easy to handle and install in circuits, but always verify the pin order before use.
-
Several common transistors like the BC546, C1815, and 2N3904 can substitute the C945, but check voltage, current, gain, and pin configuration to ensure compatibility.
-
The C945 works well in low-power amplification, relay driving, LED switching, and sensor signal conditioning, supporting up to 150mA collector current and 50V voltage.
-
Careful reading of the datasheet and proper circuit design help avoid damage and ensure the C945 transistor performs reliably in various electronic projects.
C945 Transistor Pinout
Pin Configuration
The c945 transistor uses the TO-92 package, which is common for many small-signal transistors. The c945 pinout follows a specific order that helps users connect the device correctly in circuits. The official datasheet shows the following pin arrangement when looking at the flat side of the package with the leads pointing downward:
| Pin No. | Pin Name | Description |
|---|---|---|
| 1 | Emitter | Connected to the N-doped layer; responsible for emitting electrons and carrying output current |
| 2 | Collector | Connected to the P-doped layer; acts as the output terminal |
| 3 | Base | Control terminal regulating current flow |
This Emitter-Collector-Base (EBC) configuration is unique to the c945 transistor. Some other transistors, such as the BC547, use a different pin order, so always check the c945 pinout before inserting it into a circuit.
Identifying Pins
Identifying the pins on the c945 transistor is important for proper circuit assembly. When holding the c945 with the flat side facing you and the leads pointing down, pin 1 appears on the left, pin 2 in the middle, and pin 3 on the right. The emitter sits on the left, the collector in the center, and the base on the right. This arrangement matches the c945 pinout table above.
Tip: Always double-check the c945 pinout before soldering or placing the c945 transistor on a breadboard. Incorrect pin connections can damage the transistor or cause the circuit to malfunction.
The c945 pinout makes it easy to use the c945 in various applications, from amplifiers to switching circuits. Understanding the pin configuration helps users avoid mistakes and ensures reliable performance in electronic projects.
C945 Transistor Features
C945 Transistor Datasheet
The c945 transistor stands out as a reliable NPN bipolar junction transistor. Manufacturers design it for general-purpose use in both amplification and switching circuits. The c945 datasheet highlights several important features that make this component popular in electronics projects:
-
NPN transistor type
-
Low noise operation, ideal for audio and signal circuits
-
TO-92 package for easy handling and installation
-
Silicon material for stable performance
The c945 datasheet provides a comprehensive overview of its electrical performance and operational limits. The following table summarizes the most important specifications:
| Parameter | Typical Value / Description |
|---|---|
| Transistor Type | NPN Bipolar Junction Transistor (BJT) |
| Collector Current (Ic) | 150mA |
| Collector-Emitter Voltage (Vceo) | 50V |
| Collector-Base Voltage (Vcbo) | 60V |
| Emitter-Base Voltage (Vbe) | 5V |
| Collector-Emitter Saturation Voltage | 0.2V – 0.4V |
| DC Current Gain (hFE) | 60 – 700 |
| Transition Frequency (ft) | 150MHz |
| Maximum Power Dissipation | 625mW |
| Operating Temperature Range | -55°C to +150°C |
| Package Type | TO-92 |
These specifications show that the c945 transistor can handle moderate voltages and currents, making it suitable for many low-power amplification and switching applications.
Electrical Specs
The c945 transistor offers a set of electrical characteristics that support its versatility in electronic circuits. The c945 datasheet lists the following key electrical specs:
-
Collector current up to 150mA allows the c945 to drive small loads or act as a signal amplifier.
-
Collector-emitter voltage rating of 50V ensures safe operation in circuits with moderate voltage levels.
-
Collector-base voltage of 60V and emitter-base voltage of 5V provide additional protection against voltage spikes.
-
The c945 current gain (hFE) ranges from 60 to 700, which means the transistor can amplify weak signals effectively.
-
Transition frequency of 150MHz supports use in both audio and high-frequency circuits.
-
Collector-emitter saturation voltage between 0.2V and 0.4V enables efficient switching with minimal power loss.
-
Maximum power dissipation of 625mW allows the c945 to operate reliably without excessive heat buildup.
Note: The c945 transistor’s low saturation voltage and high gain make it a preferred choice for low-power amplification and switching tasks.
Key Characteristics
The c945 transistor’s main characteristics make it a favorite for both hobbyists and professionals. Its NPN structure and silicon construction provide stability and reliability. The TO-92 package makes it easy to handle and install on breadboards or PCBs.
Key c945 features include:
-
Low noise performance, which is essential for audio pre-amplifiers and sensitive signal circuits.
-
High current gain, supporting effective amplification in low-power applications.
-
Wide operating temperature range, from -55°C to 150°C, ensures the c945 works well in various environments.
-
Compatibility with other general-purpose transistors, such as the C1815 and BC546, offers flexibility in circuit design.
The c945 transistor excels in low-power amplification, especially in audio and low/medium frequency circuits. Designers often use it in pre-amplifiers, oscillators, and small signal switching. The c945 datasheet confirms its suitability for these roles, thanks to its balanced combination of voltage, current, and gain specifications.
C945 Transistor Equivalents
Common Alternatives
Many engineers and hobbyists look for a c945 equivalent when the original part is unavailable. Several transistors share similar characteristics with the c945 transistor, making them suitable replacements in most circuits. The most common alternatives include:
-
2N3904
-
C1815 (2SC1815)
-
BC547
-
BC546
-
2N2222
-
S8050
-
BC337
These transistors appear frequently in technical guides and electronics forums as reliable substitutes. For example, the 2N3904 and C1815 offer similar voltage and current ratings, and both perform well in low-noise preamplifier and tone control circuits. The BC547 and BC546 also match the c945 transistor in many general-purpose applications, though their maximum current ratings may differ. The 2N2222 supports higher collector current, which can be useful for circuits that require more power.
| Transistor | Max Collector Current (Ic) | Max Voltage (Vce) | Gain (hFE) | Pinout Order |
|---|---|---|---|---|
| C945 | 150mA | 50V | 60–700 | EBC |
| 2N3904 | 200mA | 40V | 100–300 | EBC |
| C1815 | 150mA | 50V | 70–700 | EBC |
| BC547 | 100mA | 45V | 110–800 | CBE |
| 2N2222 | 500mA | 40V | 35–300 | EBC |
Note: Always check the pinout order before replacing the c945 transistor, as some equivalents use a different arrangement.
Substitution Tips
Selecting the right c945 equivalent requires careful attention to several key factors. The following tips help ensure a successful substitution:
-
Compare the maximum collector-emitter voltage (Vce) of the replacement with the original c945 transistor. The substitute should meet or exceed the circuit's voltage requirements.
-
Check the maximum collector current (Ic). The replacement must handle the same or higher current as the c945.
-
Review the DC current gain (hFE). For amplification circuits, similar gain ensures stable performance.
-
Confirm the transition frequency (ft) of the substitute exceeds the circuit's operating frequency, especially in audio or RF applications.
-
Examine the pinout configuration. Some transistors, like the BC547, use a CBE order instead of EBC. Incorrect pin connections can damage the device.
-
Consider power dissipation and thermal management. The replacement should match or surpass the c945 transistor's power rating.
-
Use datasheets to verify all specifications before making a substitution.
Tip: Circuit design often sets biasing and gain, so minor differences in transistor gain may not affect performance. However, always test the circuit after substitution to ensure reliable operation.
These guidelines help users choose the best c945 equivalent for their project. Careful comparison of specifications and pinouts prevents circuit failures and supports successful repairs or upgrades.
C945 Transistor Applications
Amplification Uses
The c945 transistor serves as a popular choice in audio and signal amplification circuits. Many engineers select the c945 for pre-amplifier stages in radios, microphones, and guitar amplifiers. The high current gain and low noise characteristics help boost weak signals without introducing unwanted distortion. In audio mixers, the c945 transistor often appears in tone control and equalizer circuits. Designers also use the c945 in sensor signal conditioning, where it amplifies small voltage changes from temperature or light sensors.
A typical c945 application in amplification involves connecting the transistor in a common-emitter configuration. This setup increases the input signal strength and drives speakers or further processing stages. The c945 transistor supports low-power amplification tasks, making it suitable for battery-powered devices.
Tip: For best results, users should keep the input and output coupling capacitors close to the c945 transistor. This practice reduces noise and improves audio clarity.
Switching Uses
Switching applications represent another major area for the c945 transistor. Designers use the c945 to control relays, LEDs, and small motors in automation projects. The c945 acts as an electronic switch, turning loads on or off in response to a control signal at the base. In digital logic circuits, the c945 transistor enables interfacing between microcontrollers and higher voltage devices.
Common switching applications include:
-
LED blinkers and light chasers
-
Relay drivers for home automation
-
Motor control in toys and small robots
-
Logic level shifting in embedded systems
-
Signal isolation in sensor circuits
The c945 transistor handles up to 150mA collector current, which suits most low-power switching applications. Users should always check the load requirements before selecting the c945 for switching tasks.
Note: When using the c945 in switching applications, always add a base resistor to limit current and protect the transistor.
The versatility of the c945 makes it a staple in both amplification and switching applications. Engineers and hobbyists rely on its stable performance for a wide range of c945 applications in modern electronics.
Package and Comparison
TO-92 Package
The C945 transistor comes in the TO-92 package, which is popular for small-signal devices. The TO-92 package features a compact, rectangular body with three leads arranged in a triangular pattern. The typical c945 dimensions measure about 3.9 mm in length, 3.9 mm in width, and 6.5 mm in height. This small size allows engineers to fit the c945 into space-limited designs. The c945 package supports easy manual soldering and breadboard use, making it ideal for both prototyping and production.
The TO-92 package provides strong mechanical stability and effective heat dissipation. These features help the c945 transistor maintain reliable performance in moderate power applications. The leads of the c945 package are spaced for easy insertion into standard circuit boards. Many general-purpose transistors, such as the BC547 and 2N3904, also use the TO-92 package, which highlights its versatility.
Note: Always check the c945 dimensions and pin configuration before replacing or installing the transistor to ensure a proper fit and function.
| Parameter | C945 Transistor | BC547 Transistor | 2N3904 Transistor | S8050 Transistor |
|---|---|---|---|---|
| Package Type | TO-92 (through-hole) | TO-92 (through-hole) | TO-92 (through-hole) | TO-92 (through-hole) |
| Current Rating (Ic) | 150mA | 100mA | 200mA | N/A |
| DC Current Gain (hFE) | 60 - 400 | 110 - 800 | Comparable | Higher gain |
| Pinout Configuration | Emitter-Base-Collector (EBC) | Collector-Base-Emitter (CBE) | N/A | N/A |
| Mechanical Stability | High | High | High | N/A |
| Application Suitability | Moderate power amplification, switching | Low power amplification, switching | General purpose | High gain amplifier |
C945 vs C1815
The C945 and C1815 transistors both serve as general-purpose NPN devices, but they show important differences in performance. The C945 transistor supports a higher collector-emitter voltage, rated at 45V, while the C1815 handles up to 30V. This higher voltage rating makes the c945 suitable for circuits that require more voltage tolerance, such as motor drivers or power switches.
The C945 transistor also features a collector current up to 0.2A and a power dissipation range between 600mW and 800mW. These values allow the c945 to operate under moderate loads with proper heat management. The c945 offers a low collector-emitter saturation voltage, typically between 0.2V and 0.4V, which enables efficient and fast switching in relay or LED driver circuits.
In contrast, the C1815 provides a higher current gain (hFE), often around 200, compared to the c945's typical gain of 100. This higher gain makes the C1815 better suited for high amplification tasks, such as audio preamplifiers. The c945, with its lower gain but higher voltage rating, excels in switching applications and moderate power circuits.
| Parameter | C945 Transistor | C1815 Transistor |
|---|---|---|
| Collector-Emitter Voltage (Vce) | 45V | 30V |
| Collector Current (Ic) | 0.2A | 0.15A |
| Power Dissipation | 600–800mW | 400mW |
| Current Gain (hFE) | ~100 | ~200 |
| Saturation Voltage (Vce(sat)) | 0.2V – 0.4V | Similar |
| Application Focus | Switching, moderate power | High gain amplification |
Tip: Choose the c945 transistor for switching and moderate power circuits. Select the C1815 for applications that demand higher signal amplification.
The c945 transistor stands out as a reliable choice for both beginners and professionals. This NPN device features a straightforward pinout and supports a wide range of electronic projects. Key points include:
-
The c945 transistor offers low noise, high gain, and a low saturation voltage, making it ideal for audio, switching, and signal amplification.
-
Its TO-92 package allows easy integration into most circuit boards.
-
Common equivalents like BC546 and C1815 provide flexibility in design.
Understanding the c945’s datasheet and pin configuration helps users troubleshoot and build effective circuits.
C945 VS BC547
The C945 and BC547 are both NPN bipolar junction transistors (BJTs) frequently used in low-power general-purpose applications. Although they serve similar roles in electronic circuits, they exhibit some notable differences in their electrical specifications and physical configuration.
Electrical Characteristics:
The C945 transistor typically supports a higher maximum collector current of 150 mA, compared to 100 mA for the BC547. On the other hand, the BC547 generally offers a wider DC current gain (hFE) range, typically from 110 to 800, while the C945 usually ranges from 60 to 400.
Voltage Ratings:
In terms of voltage handling, the C945 has a maximum Collector-Emitter Voltage (VCEO) of 50 V, whereas the BC547 is rated slightly lower at 45 V.
Pinout Configuration:
A key physical difference lies in the pinout layout. The C945 generally uses the Emitter-Base-Collector (E-B-C) configuration, while the BC547 follows the Collector-Base-Emitter (C-B-E) layout. This distinction must be considered when substituting one for the other.
Availability and Popularity:
Both transistors are readily available in the market. However, the BC547 is more commonly used and widely supported in modern circuit designs, whereas the C945 may be less prevalent.
Substitution Potential:
In many applications, the BC547 can serve as a substitute for the C945, provided that attention is paid to the differences in pin configuration and slightly varying electrical characteristics. Functionally, both transistors are suited to similar low-power amplification and switching tasks.
C945 Transistor Price
The price of the C945 transistor can vary depending on factors such as quantity, supplier, and location. Generally, the C945 transistor is an inexpensive component, with prices ranging from a few cents to a few dollars per unit, making it affordable for a wide range of electronic projects and applications. It is advisable to check with electronic component distributors or online retailers to obtain the most up-to-date and accurate pricing information.
FAQ
What is the maximum voltage rating for the C945 transistor?
The C945 transistor can handle a maximum collector-emitter voltage of 50V. This rating allows it to work safely in most low and medium voltage circuits.
Can the C945 transistor drive a relay or motor?
The C945 transistor supports up to 150mA collector current. It can drive small relays or motors. For larger loads, engineers should select a transistor with a higher current rating.
How does the C945 compare to the 2N3904?
Both transistors serve as general-purpose NPN BJTs. The 2N3904 offers a slightly higher current rating. The C945 provides a higher voltage rating. Users should check pinout and gain before substituting.
What happens if I connect the C945 pins incorrectly?
Incorrect pin connections can damage the transistor or cause circuit failure. Always check the datasheet and verify the pinout before installation.
Written by Jack from AIChipLink.
AIChipLink, one of the fastest-growing global independent electronic components distributors in the world, offers millions of products from thousands of manufacturers, and many of our in-stock parts is available to ship same day.
We mainly source and distribute integrated circuit (IC) products of brands such as Broadcom, Microchip, Texas Instruments, Infineon, NXP, Analog Devices, Qualcomm, Intel, etc., which are widely used in communication & network, telecom, industrial control, new energy and automotive electronics.
Empowered by AI, Linked to the Future. Get started on AIChipLink.com and submit your RFQ online today!
