Understanding C1815 Transistor: Pinouts, circuit symbols, application circuits

The C1815 transistor, a versatile and efficient staple in electronic circuits, will be our focus. We'll explore its construction, symbols, and applications, delving into the details that make it a popular choice.

The C1815, an NPN bipolar junction transistor, excels in audio amplification and high-frequency oscillation circuits. Suited for sub-50V DC operations, its 50V collector-to-base voltage is apt for lower voltage circuits.

Boasting a 150mA collector current, it adeptly powers loads under this threshold. The C1815's harmony of power dissipation and DC current gain renders it ideal for audio and signal amplification.

C1815

The C1815 transistor serves the dual purpose of amplifying audio signals and switching active loads up to 150mA. This device, crafted from silicon, carries three pins and suits high-frequency applications, denoted by the "2S" prefix. Its negative-positive-negative pin arrangement is deliberate for efficient signal routing and amplification.

The transistor's first negative terminal ties to the circuit's negative side, orchestrating electron flow to the positive core. The second negative manages electron egress. The leads—emitter, base, and collector—are distinct: the emitter dispatches the output, the base governs access, and the collector manages input.

For example, when the C1815 transistor is used in an audio/visual application, the emitter drives the audio/visual output signal. This is managed by the base, which can be grounded to the audio/visual signal, and driven by the collector, which can be a 5V supply.

The power range from the collector to the emitter can be varied by modulating the current at the base of the C1815 transistor. For example, in digital circuits, the transistor is on when exposed to 5 volts and off when below that threshold.

C1815 Triode Pinout

1. Circuit Symbol Model Diagram for C1815

Circuit Symbol Model Diagram for C1815

2. 3D model drawing of C1815

3D model drawing of C1815

• The C1815 triode has a maximum to minimum current gain of 25 to 700hFE, which is an important indication of gain capability.
• The peak collector current of the C1815 triode is 150mA, which is the maximum load current allowed for this triode.
• The peak base current of the C1815 triode is 50mA, which is the maximum trigger-side bias voltage allowed.
• The power consumption of the C1815 triode is 400mW, this particular value indicates the maximum power consumption of the C1815 triode.
• The switching frequency of the C1815 triode is 80MHZ, which is an important factor for the switching frequency of the C1815 triode.
• The maximum junction temperature of the C1815 triode is 125°C. The maximum junction temperature of the C1815 triode is 125°C.

• Package type: TO-92
• Transistor type: NPN
• Collector current (IC): 150 mA
• Collector-emitter voltage (VCE): 50 V
• Collector-base voltage (VCB): 60 V
• Emitter-base voltage (VEBO): 5 V
• Collector dissipation (Pc): 400 mW
• Conversion frequency (fT): 80 MHz
• DC current gain (hFE): 70 - 700
• Storage and operating temperature: -55 to +150 °C

The C1815 is a widely used NPN transistor. Commonly used in audio amplifiers, small audio amplifiers (when used to drive small speakers), preamplifiers and preamplifier stages, the C1815 can also be used as a switch in electronic circuits to drive loads up to 150mA. For example, to drive relays, high power transistors, low power LEDs and other parts of electronic circuits, and can also be used to make Darlington pairs.

1.C1815 for preamplifier circuits

Preamplification circuits are the most common application of the C1815 transistor.

As shown in the figure below, only four components are used for preamplification.

The capacitor at the input bypasses the DC content of the signal and the resistor provides a good path for the signal.

The C1815 transistor generates the amplified signal and flows through the output capacitor to the second stage.

C1815 for preamplifier circuits

2.C1815 triode as a switch

The figure below shows a model circuit of a C1815 transistor as a switch.

The circuit uses two LEDs on the emitter and collector terminals of the C1815 transistor.

When the switch is closed, the transistor trigger starts from the resistor and acts as a switch for the two LEDs.

C1815 transistors are typically used in high frequency circuits and the switching capability of the transistor is utilized in this application.

3.C1815 transistor amplifier circuit

The circuit shown below is a simple amplifier circuit using a C1815 transistor.

As shown below it is a common emitter configuration amplifier as if we were passing an audio signal to the input of a transistor

The C1815 transistor gives a good output of the amplified signal and the bias voltage supplied on the amplifier is rated at 4vDC.

C1815 transistor amplifier circuit

4.C1815 Other applications

• Sensor Circuits
• Audio Preamplifiers
• Audio amplifier stage
• Switching load less than 150mA
• RF Circuit
• Push-pull configuration circuit
• Driver Amplifier Stage

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