2N3055 TRANSISTOR MOUNT SERIES
But these "big old" silicon transistors are work-horse silicon power devices as active load devices and series bypass regulators, just don't try to push it to 200'C max spec and expect it to last too long. There are also TO-247 NPN power transistors with insulated mounting holes. You can learn a lot by studying other designs.
2N3055 TRANSISTOR MOUNT PC
You can often get old ones free or cheap surplus from PC shops. Well normally the 2N3055 wouldnt go into a PCB, it would go into a TO-3 socket mounted on a heat-sink. Also the surface needs to be large enough to ensure it is also very flat as any air gap insulates the part or adds 'C/Watt like Ohms Law for temperature rise.įor tips on cooling look at some CPU heatsinks for 100Watts both passive and force air cooling and compare your requirements. This article enforces datasheet, pinout, applications, schematic. The MJ2955 is a silicon PNP transistor in a TO3 type case designed for general purpose switching and amplifier applications. Bipolar Transistors - BJT PNP Power Switching. read "increases the case-air thermal resistance. MJ2955 PNP Transistor: Pinout, Datasheet, and Equivalents. The electrical insulator is necessary next to the transistor to prevent shorts since you can't really enclose a "live" heatsink as that insulates it. You would be better off with a TO-220 and larger thermal mass and surface area. Either you underestimated the temperature rise of this 15 amp transistor or you just happen to prefer bulky parts over the TO-220 plastic cases with metal tabs and are hoping for the best.
So yes I would say there is something wrong with this picture. It would be like using jumper cables to drive 10 Watt speakers. Semicoa specializes in the manufacture of discrete silicon semiconductors focusing on small signal transistors for military, aerospace and space industries globally. 5PCS Transistor 2N3055 3055 to-3 15A 60V NPN AF Amp Audio Power New. Now considering you got this really big low thermal impedance transistor, does it make sense to mount it on a really "high" resistance small chunk of extruded aluminum metal. Encontre Transistor 2n6121 no MercadoLivre. No heat sink gives you 50 to 70'C/Watt junction to ambient thermal resistance.Ĭonsidering your heatsink may only increase the "effective" surface area of the TO-3 by eyeball, a factor of 4, I would estimate your thermal resistance is around 12'C/Watt.
The 2N3055 pass transistor must be mounted on an adequate heatsink.The advantage of the TO-3 case is <1.6'C/Watt thermal resistance vs the TO-220 of <1.8'C/Watt. A 1 kOhm output resistor provides stability for the power supply under no - load conditions. A 100uF electrolytic capacitor is used for ripple voltage reduction at the output. Since desired output of the supply is 1 Ampere, maximum current limit is set to 1,5 Ampere by resistor Rsc whose value is 0,422 Ohm. A 100-pF capacitor from pin 13 to pin 4 furnishes gain compensation for the amplifier.īase drive to the 2N3055 pass transistor is furnishes by pin of the uA723. For fine trimming the output voltage, a potentiometer can be installed between R1 and R2. The reference terminal at pin 6 is tied directly to pin 5, the non inverting input of the error amplifier.
The output through R1 and R2, providing about 7 V with respect to ground at pin 4. This applied to pin 11 and 12 of the IC uA723/LM723, as well as to the collector of the 2N3055 series pass transistor. While testing this, the 2N3055 keeps dying when the. Please note: R1 is a 10k NTC thermistor, R6 and R8 are part of a 10k pot, R9 is a power resistor mounted on a heatsink, and the 2N3055 is also mounted on a heatsink for testing. The 2N3055 is just a single power transistor, not a Darlington, and has hFE 5 10A. Im trying to build a water heater based on a 2N3055 transistors power dissipation. They have the same package and about the same max current/power rating however the 2N6576 is a Darlington transistor (internally, one transistor driving another one) and has hFE 100 at 15A. Then receives +20 Volts DC from rectifier / filter section. BTW, the 2N3055 and 2N6576 arent even slightly similar. The supply receive from 220 /120/110 Volt AC, then lowered by the transformer.
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