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Unijunction Transistor
Description:
A PN unijunction transistor in a TO–92 type package
designed for use in pulse and timing circuits, sensing circuits and
thyristor trigger circuits
Absolute maximum Ratings:
(Ta = +25°C unless otherwise specied)
Power Dissipation, Pd : 300mW
Derate Above 25°C : 3.0mW/°C
RMS Emitter Current, Ie(rms) : 50mA
Peak Pulse Emitter Current (Note 1) Current, ie : 1.5A
Emitter Reverse Voltage, Vb2e : 30V
Interbase Voltage, Vb2b1 : 35V
Operating Junction Temperature Range, Tj : -65°C to +125°C
Storage Temperature Range, Tstg : -65°C to +150°C
Notes:
1. Duty Cycle <
=
1% PRR = 10PPS.
2. Based upon power dissipation at Ta = +25°C
3. Intrinsic standoff ratio is essentially constant with temperature and interbase voltage and is dened by the equation:
Vp – Vbb + Vd
Where: Vp = Peak Point Emitter Voltage; Vbb = interbase Voltage;
Vd = Junction Diode Drop (~0.5V).
4. Use Pulse techniques: Pulse width ~ 300µS, Duty Cycle <
=
2% to avoid internal heating due to interbase modulation which
may result in erroneous readings.
Electrical Characteristics: (Ta = +25ºC Unless otherwise specied)
Parameter Symbol Test Conditions Min Typ Max Unit
Instrinsic Standoff Ratio Vb2b1 = 10V, Note3 0.70 - 0.85 -
Interbase Resistance rbb 4.0 6.0 9.1 kΩ
Interbase Resistance Temperature
Coefcient 0.1 - 0.9 %/ºC
Emitter Saturation Voltage Veb1(sat) Vb2b1 = 10V, Ie = 50mA, Note 4 - 2.5 - V
Modulated interbase Current Ib2(mod) Vb2b1 = 10V, Ie = 50mA - 15 - mA
Emitter Reverse Current Ieb20 Vb2e = 30V, Ib1 = 0 - 0.005 1 µA
Peak Point Emitter Current IpVb2b1 = 25V - 1 5 µA
Valley Point Current IvVb2b1 = 20V, Rb2 = 100Ω, Note 4 4 7 - mA
Base-One Peak Pulse Voltage VOb15 8 - V
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Page <2> V1.010/09/12
Unijunction Transistor
Important Notice : This data sheet and its contents (the “Information”) belong to the members of the Premier Farnell group of companies (the “Group”) or are licensed to it. No licence is granted
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Multicomp is the registered trademark of the Group. © Premier Farnell plc 2012.
Part Number Table
Description Part Number
Unijunction Transistor, TO-92, PN 2N4871
Dim Min Max
A 4.32 5.33
B 4.45 5.2
C 3.18 4.19
D 0.41 0.55
E 0.35 0.5
F
G 1.14 1.4
H 1.14 1.53
K 12.7
Dimensions : Millimetres