Questions tagged [junction]

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1answer
29 views

Thermal resistance Junction - Maximum Power dissipation

I want to understand the real meaning of the parameter 'Thermal Resistance Junction to Air (°C/W) to calculate the power dissipation. So for example if the value of this parameter is 250°C/W, should I ...
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3answers
68 views

Failed to plot junction capacitance versus reverse voltage in LTspice

The 1N4001 diode's junction capacitance versus reverse voltage plot is given as follows: I guess to measure this capacitance they applied 1MHz 50mV pk-pk sine wave signal as reverse biased and varied ...
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4answers
203 views

1N5822 schottky diode heatsinking

Is the cathode for schottky diode hotter than the anode, as is common for most diodes, or is it reverse polarity? A schottky is a metal-semiconductor junction, with the metal at the anode. So it ...
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1answer
64 views

Li-Ion Battery Charging Board Temprature (Junction Temp)

I'm looking for a little help with a simple battery charging project. I've bought a pack of cheap USB charging boards on ebay (link) with the intent of using one to charge a small Li-Ion battery. ...
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2answers
1k views

What does it mean bipolar or unipolar junction in a transistor?

I can't find the definition of unipolar and bipolar junction in a transistor, for example BJTs has a bipolar junction and MOS-FET has a unipolar junction, what does it mean unipolar and bipolar ...
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2answers
100 views

Evaluating junction temperature from thermal imaging data

I have a SOD-123F diode through which a current of ~1A flows, creating a forward voltage drop of around 300mV. The datasheet does not specify Rjc but gives Rja = 200 C/W and Rjl = 70 C/W for a 10cm x ...
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1answer
426 views

Collector-Emitter short but not Base-Emitter

I have a power amp that blew the pair of transistors(2SD1047 and 2SB817) at the output. The positive side 1047 is totally shorted, all junctions, the negative side 817 is only shorted Collector-...
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2answers
102 views

Relationship between junction area and voltage in forward biasing

What is the relationship between junction area and voltage in forward biasing? My book said that the voltage to establish forward biasing increases with decreasing of junction area. Why? EDIT: The ...
3
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1answer
71 views

Why can't current go through two voltage source junction?

I crossed out the middle because it felt like it wouldn't make sense. (Mostly because i felt like conservation of current was violated.) But im not sure why it wont go through at that particular ...
1
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2answers
648 views

Why don't the minority carriers combine with the majority carriers in a PN junction?

I wanted to start this question by giving my understanding of the make up of a PN junction. I do this so that you can pick me up on anything that I may be getting wrong in the lead up to my question. ...
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2answers
183 views

Is there any junction, or branch element for jumper cables?

I would like to create circuits using jumper cables. I have male-female, male-male, and female-female jumper cables too. But I cant find any branching cable on ebay. What should I use, to create ...
2
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1answer
947 views

Calculating maximum power dissipation based on contact area between two metal conductors

I am trying to figure out how to properly calculate the minimum contact surface area based on the maximum required power dissipation. Let me explain.. I am creating a custom semi-circular metal tab ...
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1answer
111 views

IC Thermal shutdown recovery time

Many RS485 transceiver chips have a thermal shutdown when the junction exceeds 150C. Typically they switch back on once the junction temperature drops 15 degrees. How long does that typically take? ...
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5answers
2k views

Where is the cold junction on the commercial thermocouples?

According to all textbooks and articles, a thermocouple must have a cold junction somewhere on the middle of it. But none of the commercial products have a middle point or a marked spot for ...