Introduction to BC560

Introduction to BC560

• BC560 is a PNP transistor mainly used for switching and amplification purpose. It comes with transition frequency 150MHz and junction temperature of 150 C.
• This PNP transistor contains three pins called emitter, base, and collector. These pins are used for external connections with the electronic circuit. The small current at the base side is used to produce large current change across other terminals.
• BC560 carries three layers where one is the n-doped layer that represents the base terminal and the other two are p-doped layers that represent emitter and collector respectively. The n-doped layer stands between two p-doped layers.

• As this is a PNP transistor, here current flows from emitter to collector as opposed to NPN transistor where current flows from collector to emitter.
• Also, here in PNP transistor holes are majority carriers… even though both electrons and holes play a key role in the conductivity of PNP transistors, here holes are majority carriers in contrast to NPN transistors where electrons are majority carriers.

• In both cases, however, the base terminal is the main component responsible for the overall electron action. Which is positive in the case of NPN transistor and is negative in the case of PNP transistor.
• Moreover, all these terminals are different in terms of their functionality and doping concentrations. The emitter side is more doped as compared to the other two terminals.
• Plus, the emitter terminal contains the overall transistor current. The emitter current is a sum of both collector and base current.

BC560 Datasheet

BC560 Pinout

• These terminals are used for external connection with the circuit.
• The following figure shows the pinout of the BC560 transistor.

• It is wise to pay special heed to the pinout of the transistor before employing it in your project.
• Installing the component with the wrong configuration can damage the component and thus the entire project.

BC560 Working Principle

• The working principle of this PNP transistor is almost similar to NPN. In both cases, the base terminal triggers the transistor action.
• When there is no current available at the base terminal, the transistor is turned ON and both collector and emitter terminals are forward biased.
• And when current flows from the base side, the transistor is turned OFF, indicating both emitter and collector pins are reverse biased.

• It is important to note that… even though NPN and PNP transistors are used for amplification purposes, NPN transistors are preferred over PNP transistors since the mobility of electrons is far better and quicker than the mobility of holes.

BC560 Power Ratings

• The collector-emitter and collector-base voltages are 45V & 50V respectively. While emitter-base voltage is 5V that means the only 5V is required to start the transistor action.
• The transition frequency is 100MHz and junction temperature is 150 C. The collector current is 100mA, projecting it can support loads under 100mA.

• These are the stress ratings which if exceed the required ratings, can hurt the device. And if you apply these ratings more than the required time they can damage the device reliability.

Difference between PNP and NPN Transistors

• Both NPN and PNP transistors operate almost in a similar fashion. The base pin is the main terminal that plays a key role in triggering the transistor action in both cases.
• The emitter side is highly doped and contains the entire current of the transistor.
• Voltage polarities and current directions create a difference between both NPN and PNP transistors.
• Current flows from collector to emitter in case of NPN transistor while it flows from emitter to collector in case of PNP transistors. The base is negative in PNP transistor while it’s positive in the case of NPN transistor.

• Recall, mobility of electrons is better than the mobility of holes, the reason NPN are preferred over PNP for amplification purposes.
• The base terminal acts as a control value in both cases where it controls the holes in PNP transistor and it controls the electrons in case of NPN transistor.

• Note that, both PNP and NPN transistors are interchangeable only if a bipolar junction transistor is made up of two back-to-back diodes with the base terminal as the common terminal.

BC560 Alternatives

• BC860W (SOT-323)
• BC857W (SOT-323)
• BC857 (SOT-23)
• BC860 (SOT-23)

BC560 Applications

• Used in current mirror circuits.
• Used for switching and amplification purpose.
• Employed for constructing Astable bistable multivibrators.
• Employed for impedance buffering.
• Incorporated to drive loads under 100mA.
• Finds applications in H- Bridge circuits.
• Used in comparator and oscillator circuits.

BC560 Physical dimensions