2N2646 UJT transistor
2N2646 UJT transistor electrical specification
- 2N2646 is a general-purpose PN unijunction transistor device
- Emitter reverse voltage (VB2E) is 30V
- Inter-base voltage (VB2B1) is 35V
- RMS emitter current (Ie) is 50mA
- Power dissipation is 300mW
- Junction temperature is between -65 to 150℃
- Emitter saturation voltage (VEBI (SAT)) is 5V
- Inter-base resistance (RBB) is 7 to 9.1kΩ
- High reliability
- Low emitter reverse current
- Low peak point current
- Passivated surface for reliability & uniformity
- Low saturation voltage
2N2646 UJT transistor Pinout
| Pin Number | Pin Name | Description |
| 1 | BASE 1 | Connected to power source |
| 2 | EMITTER | The emitter terminal is used to trigger the device |
| 3 | BASE 2 | Connected to load |
| 4 | CASE | The case is been connected with base2 internally |
2N2646 UJT transistor package
The device package used at the 2N2646 transistor is TO-18, it is a general-purpose power transistor package.
TO-18 package is made with metal, this is why these transistors had higher temperature capacity and compactness.
The 2N2646 UJT transistors are general-purpose devices mainly used for small circuit applications, this TO-18 package is apt as a compact electronic component.
2N2646 UJT transistor electrical specification description
In this section, we try to explain the electrical specifications of the 2N2646 UJT transistor device.
Voltage specs
The terminal voltage specs of the 2N2646 transistor are emitter reverse voltage is 30V, inter-base voltage is 35V.
The emitter saturation voltage is 2.5V
The voltage specifications of 2N2646 UJT show, that it is a general-purpose transistor device.
Current specs
The RMS emitter current is 50mA, it is the current for triggering the 2N2646 UJT transistor.
Dissipation specs
The power dissipation of the 2N2646 UJT transistor is 300mW, the dissipation capability will mainly depend on the device package.
Junction temperature
The junction temperature of -65 to 150℃, which is a general-purpose transistor temperature value of capacity.
Inter-base resistance
The inter-base resistance is the overall resistance of the 2N2646 UJT transistor, it is between 4.7 to 9.1kΩ.
2N2646 UJT transistor DATASHEET
If you need the datasheet in pdf please click this link
2N2646 UJT transistor equivalent
The transistor devices such as 2N2647, 2N4871, 2N4870, and 2N1671 are the equivalent UJT transistors of 2N2646.
Most of the electrical specifications of these transistors are the same as the 2N2646 device, so we can easily replace them at circuits.
2N2646 vs 2N4871
In the table below we list the electrical specifications of 2N2646 vs 2N4871 UJT transistor.
| Characteristics | 2N2646 | 2N4871 |
|---|---|---|
| Emitter reverse voltage (VB2E) | 30V | 30V |
| Inter-base voltage (VB2B1) | 35V | 35V |
| RMS emitter current (Ie) | 50mA | 50mA |
| Emitter saturation voltage (VEBI (SAT)) | 2.5V | 2.5V |
| Power dissipation | 300mW | 300mW |
| Junction temperature (TJ) | -65 to +150°C | -55 to +150°C |
| Inter-base resistance (RBB) | 4.7 to 9.1kΩ | 4 to 9.1kΩ |
| Package | TO-18 | TO-92 |
The 2N2646 and 2N4871 transistors had the same electrical and physical characteristics.
2N2646 UJT transistor applications
- General-purpose industrial applications
- Tuner circuits
- Sensing circuits
- Trigger circuits
- SCR firing circuits
- DIY making
- Phase control circuits
- Used at SAW tooth wave generator circuit
- Voltage detector
- Hobby circuits
