BD135 transistor is a bi-polar, medium-power, plastic nPn transistor made up of silicon. It is used in a wide range of electronic equipment especially used as an audio signal amplifier and drivers using complimentary or quasi complimentary circuits. The transistor has three regions of different conductivity with two NPN junctions. The two end regions have same conductivity known as Emitter and collector while the middle region with different conductivity is known as base.
BD135 Transistor Characteristics:
- Audio signal amplifier
- Polarity is NPN
- High current (maximum 1.5A)
- Low Voltage (maximum 80V)
- Collector current = 1.5 A
- Base current = 0.5A
- Collector base voltage = 45V
- Collector emitter voltage = 45V
- Emitter base voltage = 5V
- It is lead (Pb) and Halogen free
The transistor has three pins labeled as emitter, base and collector as shown in fig.
BD135 Circuit Diagram:
BD135 transistor is used in low cost universal battery charger. Circuits for nickel cadmium and nickel metal hydride batteries charger contain this transistor and are best for car use. This charger has selectable charging current. And it is able to charge phones, mp3 and video players, toys and almost all other portable electronic devices.
Q1 = BD135
C1 = 220 µF
D1 = 1N4007
D2 = LED 3mm
R1 = 120 Ω
R2 = given in circuit diagram
J1 = DC input socket
Input voltage varies from 6.5V (min) to 21V (max) depending upon the battery. The input selection table is given below.
BD135 Equivalent Transistors:
Characteristics of BD137 and BD139:
|Collector base voltage (VCBO)|
|Collector emitter voltage (VCEO)|
Emitter base voltage(VEBO)