Skip to Content
  1. All Products
  2. Transistors BJT
  3. PNP Transistor BC 557 (BJT)
Pricelist: - Pricelist

PNP Transistor BC 557 (BJT)

🔋 BC557 – PNP Bipolar Junction Transistor (BJT)

The BC557 is a general-purpose PNP transistor commonly used in low-power switching and amplification applications. It pairs well with the BC547 or BC549 (NPN) as a complementary device, making it ideal for push-pull amplifier designs, signal inverters, and transistor logic circuits.

⚙️ Technical Specifications

ParameterSpecification
Transistor TypePNP BJT
Max Collector-Emitter Voltage45V
Max Collector Current100 mA
Max Power Dissipation500 mW
DC Current Gain (hFE)110 – 800 (depending on variant)
Transition Frequency~150 MHz
PackageTO-92 (Through-hole)
Complementary NPNBC547 / BC549

📎 Pin Configuration (TO-92 Package)

markdown
CopyEdit
   FRONT VIEW
   _______
  |       |
  |       |
  |_______|
   | | |
  C B E

  • C – Collector

  • B – Base

  • E – Emitter

✅ Features

  • 🔁 General-purpose switching and amplification

  • 🎛️ Works with analog and digital signals

  • 🔌 Can be used as a signal inverter or low-side switch

  • 🧰 Breadboard and Arduino/ESP32-friendly

  • 🛠️ Pairs with BC547/BC337 for complementary circuit designs

🧪 Example Application: Inverted LED Control

In a PNP transistor, the emitter is connected to Vcc, and a LOW signal to the base turns it ON.

// Arduino example to turn on LED via PNP transistor
int ledControl = 3;

void setup() {
  pinMode(ledControl, OUTPUT);
  digitalWrite(ledControl, HIGH); // OFF
}

void loop() {
  digitalWrite(ledControl, LOW); // ON (emitter to collector flows)
  delay(1000);
  digitalWrite(ledControl, HIGH); // OFF
  delay(1000);
}

🎥 YouTube Tutorial

📺 https://youtu.be/WCwYrHcZAo4?si=K6keFsQTYrcdAncO

2.00 LE 2.00 LE

This combination does not exist.

PNP Transistor