May 14, 2008

2N4870 (SILICON UNIJUNCTION TRANSISTOR)

The General Electric 2N 4870 Silicon unijunction Transistor are intended for general purpose industrial applications where circuits economy is of primary importance. The 2N4870 are ideal for use in firing circuits for silicon controlled rectifiers, timing circuits, relaxation oscillators and other typical unijuction transistor applications.

ABSOLUTE MAXIMUM RATINGS : 25°C (unless otherwise specified)

Power dissipation( Note 1)

300mW

RMS Emitter Current

50 mA

Peak Emitter Current(Note 2)

2 A

Emitter Reverse Voltage

30 V

Interbase Voltage

35V

Operating Temperature Range

-65°C to + 125°C

Storage Temperature Range

-65°C to +150°C

ELECTRICAL CHARACTERISTICS : 25°C (unless otherwise specified)

PARAMETER

 

Min

Typ

Max

 

Intrinsic standoff Ratio (VBB=10V)

0.56

-

0.75

 

Interbase Resistancev
(VBB=3V, IE=0)

RBBO

4.0

6.0

9.1

K

Emitter saturation Voltage
(VBB=10V, IE=50mA)

VE(sat)

-

2.5

-

V

Modulated Interbase Current
(VBB=10V,IE=50mA)

IB2(MOD)

-

15

-

mA

Emitter Reverse Current
(VB2E=30v,IB1=0)

IEO

-

0.05

1.0

µA

Peak Point Emitter Current
(VBB=25V)

Ip

-

1.0

5.0

µA

Valley Point Current
(VBB=20v, RB2=100W)

Iv

2.0

5.0

-

mA

Base-one peak pulse voltage(Note3)

Vob1

3.0

6.5

-

V

Note:


1. Derete 3.0 MW/°c increase in ambient temperature.
The total power dissipation (available power to Emitter and Base- Two) must be limited by the external Circuitry.

2. Capacitor Discharge- 10Fd or less, 30 volts or less

3. The Base-one Peak Pulse Voltage is measured in the circuit below. The Specification is used to ensure a minimum pulse amplitude for application in SCR firing circuits and other types of pulse circuits.

4. The intrinsic standoff ration is essentially constant with temperature and interbase voltage.

is defined by the equation :

Vp= VBB + VD


where


Vp = Peak emitter voltage
VBB= Interbase Voltage
VD = Juction Diode Drop (Approx 5v)

Back to Data Sheet

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