This Product Selection Guide contains information to help select products in the Programmable Unijunction category on DigiKey.com
Programmable unijunction transistors (PUTs) are a relative of Silicon Controlled Rectifier (SCR) devices, having a characteristic behavior somewhat like a unidirectional DIAC with a user-configurable threshold voltage. While useful for creating low frequency oscillator and timing functions, SCR triggering applications, and others, alternative techniques for addressing such needs have gained greater favor.
SelectionCharacteristics
Voltage: Typically this represents the maximum voltage rating to which a device will meet its given specifications. Exceeding this voltage rating may damage the device and other system components.
Power Dissipation (Max): Characterizes the amount of electrical power dissipation in a device that produces a specified internal device temperature (often the rated maximum) under specified operating conditions.
Voltage - Output: The maximum output voltage the device can produce across the gate-cathode connection in reverse bias operation, while the device is providing its programmed output.
Voltage - Offset (Vt): Characterizes the difference between an applied “programming” voltage and the resulting peak anode voltage on a device’s operating curve.
Current - Valley (Iv): The current flow through the device at which the resulting voltage across the device is at a minimum; the lowest point in the device’s V-I curve.
Current - Peak: Current flow through the device at the peak of its characteristic V-I curve; the current flow required to cause the device to enter its negative resistance region.
Package / Case: Indicates the type of protective case used on an electronic component to allow easy handling, installation, and protection. This selection was determined to be the closest industry standard applicable to the supplier device packaging. Typically it is best to check the actual dimensions from the datasheet rather than depend on this terminology when designing your circuit.
ProductExamples
| MFR PART # | CMPP6028 TR PBFREE |
|---|---|
| DIGI-KEY PART # | 1514-CMPP6028TRPBFREETR-ND - Tape & Reel (TR) |
| MANUFACTURER | Central Semiconductor Corp |
| DESCRIPTION | Programmable Unijunction Transistor (UJT) 40V 167 mW TO-236-3, SC-59, SOT-23-3 |
| DATASHEET | Click Here |
| MFR PART # | 2N2646 |
|---|---|
| DIGI-KEY PART # | 2383-2N2646-ND |
| MANUFACTURER | Solid State Inc. |
| DESCRIPTION | Programmable Unijunction Transistor (UJT) 35V 300 mW TO-206AA, TO-18-3 Metal Can |
| DATASHEET | Click Here |
| MFR PART # | 2N6028 |
|---|---|
| DIGI-KEY PART # | 2368-2N6028-ND |
| MANUFACTURER | NTE Electronics, Inc |
| DESCRIPTION | Programmable Unijunction Transistor (UJT) 40V 300 mW TO-226-3, TO-92-3 (TO-226AA) |
| DATASHEET | Click Here |
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