Questions tagged [bipolar]
The bipolar tag has no usage guidance.
106 questions
-1
votes
1
answer
44
views
Ethernet ESD protection between connector and magnetic transformer, bidirectional or unidirectional?
When ESD protection is done between connector and magnetic transformer, I think the bidirectional diode is best suited since the signals are bipolar.
Why unidirectional diodes are applied in reference ...
- 47
0
votes
0
answers
50
views
Calculation of amplifying stages on bipolar transistors
please help me. i don`t understand how to do it
To develop a circuit diagram of an AC amplifier on a bipolar
transistor and calculate the values of the nominal elements of the developed
transistor ...
2
votes
1
answer
201
views
This is exactly the wrong way to connect this DC circuit breaker, is it not?
This is another little spin-off question of the main one:
DC breakers does polarity really matter? where I want to avoid that it gets flagged as a question that's moving target.
One answer that has ...
- 1,669
0
votes
0
answers
34
views
Adjusting the negative output voltage of a bipolar step-down converter in Proteus
I'm working on designing a bipolar step-down DC-DC converter with a +12V input, targeting ±5V outputs. I'm using flying capacitors for the configuration, and I'm modeling the circuit in Proteus 8.17 ...
- 9
2
votes
2
answers
88
views
Why do we use CE mode instead of CC mode?
In bipolar junction transistor, the current gain is maximum in common collector configuration but still we use the common emitter configuration (at least it is the thing that was taught to me). What's ...
1
vote
0
answers
44
views
Low-noise bipolar boost power supply
I am working on a new design, and have a clarifying question.
The circuit is powered from a 5V USB-C connector, and contains a 16-bit DAC (DAC80508) outputting 0-5V, fed into an op-amp circuit to ...
- 101
3
votes
3
answers
367
views
Bipolar analog latch circuit needed
I am struggling with the required circuit design which should latch its output if the signal (from range ±10 V DC) reaches ±1 V (or a certain predefined threshold). I have found on this site a circuit ...
2
votes
1
answer
66
views
How does the capacitance of non‐polarized or bipolar electrolytic capacitors depend on DC bias voltage?
If two identical electrolytic capacitors are connected in reverse series, then at sufficiently low voltage, they should effectively behave as two simple capacitors, which leads to a reduction in ...
- 165
0
votes
2
answers
169
views
Why my RC-oscillator design does not produce any output?
I designed this single transistor RC-oscillator circuit and implemented it on the breadboard. However, I detect no oscillations on the output.
I know that using power transistor is not the best idea ...
-1
votes
2
answers
134
views
Power supply for microcontroller
Can a microcontroller rated for 5-7V be powered by bipolar supply of +/-(2.5-3.5)V
Considering fact voltage values are only relative scale and only absolute difference matters?
A specific part number ...
- 135
3
votes
3
answers
311
views
Increasing current biases of multistage amplifiers
I remember my professor talking about op amp and he said when we have a multistage amplifier (for instance an op amp) bias current for second stage of amplification must be more than the first stage ...
1
vote
1
answer
94
views
How to confirm PNP transistor is valid?
I am practicing with some basic circuits based on bipolar and MOSFET transistors and have faced with an interesting behavior. I have to extract my PNP transistor from a circuit and have found it ...
- 131
0
votes
2
answers
91
views
Is it necessary to connect the (-) terminal to earth when connecting two bench top power supplies in series to achieve a bipolar supply?
I have noticed when researching online that it is always mentioned to connect the (-) terminal to earth when connecting two power supplies in series to create a bipolar supply. Is there any issue with ...
0
votes
1
answer
79
views
What happens when the CB junction is in forward bias and the BE junction is in reverse bias in an NPN bipolar transistor?
What happens when the CB junction is in forward bias and theBE junction is in reverse bias in an NPN bipolar transistor?
I thought of two possibilities:
The NPN transistor acts as it is but in ...
- 59
0
votes
3
answers
135
views
+/-10V input voltage to frequency converter
I need to convert a bipolar voltage to a frequency. Say -10 to +10V for the example. For the context this voltage is the error signal from an analog feedback loop. I have a schematics that works well ...
- 101
2
votes
0
answers
117
views
How to ramp a bi-polar Return to Zero (RZ) digital waveform
I am using a Raspberry Pi Pico and a few op-amps and resistors to implement an ARINC 429 transmitter. ARINC 429 is a bipolar RZ serial communication protocol commonly used in avionics. See the image ...
- 21
1
vote
1
answer
91
views
Diode and bipolar NPN transistors orientation not correct, says JLCPCB
JLCPCB is telling me 4 components are incorrect but when I look over it and the datasheet it all seems correct to me.
My original | JLCPCB corrected:
This is what my current board looks like:
My ...
- 805
0
votes
1
answer
136
views
Need help in identifying SMA package component
I have a problem with identifying a certain element in the SMA housing, which in my opinion has a marking that is inconsistent with what is given in the datasheet (the datasheet which I selected based ...
- 113
3
votes
1
answer
209
views
BJT transistor sum
Here I considered it is in active region and considered Vbe=0.6 V.
I did this:
I considered it is in active region but it Vce is less than 0.2 V.
What should I do next?
- 85
1
vote
0
answers
126
views
JFET + Bipolar source follower: with VGS constant, how Vout can be an AC signal?
Id is the sum of IB and IR1 with IB small. We can approximatively say Id equals IR1.
BJT give an voltage across R1 equals to VBE.
VR1 = VBE which is limiting the current flowing across R1. In ...
- 11
1
vote
3
answers
148
views
Adjustable power resistance
I have to design a circuit that must draw up to 1200 W on 12 VDC to 40 VDC, maximum 50 A, during 100 ms and be adjustable.
The first approach was to use power resistors (LTO100) of several values, ...
- 253
3
votes
1
answer
107
views
Is this behavior realistic for bipolar loads on optocoupler outputs?
Background:
When using LTspice to simulate such a circuit (the opto-model is called PC357NT and is part of some exhaustive lib called "ZZZ" which I downloaded a long time ago. The PC357NT ...
- 23.4k
1
vote
1
answer
460
views
Why is bipolar capacitor labelled with plus and minus?
I need an unpolarised 3300 uF capacitor for an audio amplifier. After googling on the internet, I came to the conclusion that the only way to get such a high value is to use a so-called bi-polar ...
- 585
0
votes
1
answer
136
views
Using MOSFET to prevent short circuit
I have a circuit where a charger loads a 24 V battery. When the charger is not plugged, there is a risk that of short circuit and the battery will then explode. To avoid this I thought about using ...
- 161
3
votes
0
answers
72
views
Active load and current source purpose on NE5532
I'm trying to do some reverse engineering on the NE5532 schematic, but I can't understand how is designed the current source for the first stage. What I want to analyze now is in yellow on the picture....
- 359
4
votes
0
answers
121
views
Active load role on this circuit and possible uses
simulate this circuit – Schematic created using CircuitLab
I came with this circuit to know how an active load can improve it, I still can't finish to understand the role of active loads. The ...
- 359
1
vote
1
answer
146
views
We fabricate P-type and N-type Schottky diodes and a P-type Schottky diode; can a PN-junction diode and PNP BJT be formed?
A Schottky diode is a unipolar device. If a P-type Schottky diode is fabricated on an N-type Schottky diode, can we make a PN-junction diode and a PNP transistor?
0
votes
2
answers
209
views
Layperson asking intuitive question about bipolar junction transistor
I am a layperson trying to understand how the bipolar junction transistor works from this excellent article: https://spectrum.ieee.org/transistor-history
The relevant paragraphs are as follows:
...
- 103
0
votes
0
answers
37
views
Bipolar calculations with unkown resistor values and unknown current values
Having a hard time figuring out the current and resistor values across resistor Rf and Rc in an NPN germanium transistor. How do I calulate the current across the collector of the transistor with ...
0
votes
2
answers
104
views
Is there a problem with my circuit?
The problem is that the curve of the collector's current decreases after reaching a certain (or saturation) point. Should it be this way or there is a problem with LTspice?
- 1
0
votes
0
answers
56
views
Grounding a bi polar high voltage pulser
This was a "brain teaser" in a circuits class, where only theory is required. Any equations or vocabulary to look into would be greatly appreciated. The question is the following:
You are ...
2
votes
1
answer
127
views
ADS1113 ADC saturation at 0 Volts while sampling bipolar signal
I'm using a ADS1113 delta-sigma 16-bit ADC to sample a bipolar signal from a force sensor at 50Hz, and I have found a weird phenomenon.
When the signal negative or positive, there is no issue, but ...
- 23
0
votes
1
answer
73
views
Creating bi-polar signal from IC's
I'm trying to create a bi-polar square wave from a flip flop but all I get is a positive result. It never goes below GND. I know the second (lower) transistor gets positively biased and maybe this is ...
- 355
4
votes
2
answers
181
views
What does the cross point of V-I curves mean?
Here you see a V-I graph including many curves achieved under different junction temperatures of an IGBT. As it can be seen there is a cross point where all curves intersect each other. Does it make ...
- 151
4
votes
3
answers
585
views
Pulse oximeter design: How to drive a bi-polar LED having two different forward voltages?
My lab partner and I are building a pulse oximeter for our capstone project and could use some help.
I have an ELM-4002 which is a bipolar LED with the following specifications. The two LEDs are ...
6
votes
1
answer
5k
views
BJT vs MOSFET switching speed
I've been reading various answers about the switching speed and frequency of BJTs and MOSFETs, yet I keep finding conflicting answers. Can anyone explain the discrepancy and the real answer? Sources ...
- 61
0
votes
0
answers
63
views
Is the power consumption of field effect transistors lower than that of bipolar transistors, and why? [duplicate]
Is the power consumption of field effect transistors lower than that of bipolar transistors, and why?
9
votes
4
answers
1k
views
Basic electronics: Transistor switch
I am new to electronics. I am reading this book called Practical Electronics for Inventors.
This is a portion about bipolar transistors from the book:
There are two things I don't get from this:
...
- 521
2
votes
3
answers
291
views
Physics of bipolar transistor turn-off
In a class AB follower push pull amplifier output stage* operated open loop and driven from a low impedance source, these are, from top to bottom, the emitter currents of both transistors, their ...
- 81.6k
4
votes
1
answer
295
views
Proving that this JFET + Bipolar source follower give back a linear output
I was reading about this source follower and wondered how the bipolar transistor makes Vgs somewhat stable.
I believe that what happens here is that when Vin is high more current flows through the ...
- 227
0
votes
1
answer
63
views
Where can I find the symbolic symbols of various bipolar, JFET, MOSFET in a *unified* style?
Where can I find the symbolic symbols of various bipolar, JFET, MOSFET in a unified style ?
2
votes
2
answers
853
views
Diode in feedback path of transistor (collector-base)?
This is the schematic for a fuzz circuit. Even knowing that the diode is probably what's providing the signal clipping, I still can't figure out how I'm supposed to analyze the circuit.
When V(...
- 85
0
votes
1
answer
90
views
Noise reduction in ECL logic gates
In this ECL circuit, how he got the equivalent circuit for the noise voltage and what is the meaning of hib4 in the equivalent circuit.
- 105
0
votes
1
answer
112
views
Qualitative explaination of Output Characteristic of Transistor (BJT) using Depletion layer between Collector and Base
From my understanding,
The diffusion layer at a p-n junction is an equilibrium of two opposing forces on charge carriers due to 2 forces - Concentration Gradient and Electric Field caused by Bias and ...
0
votes
1
answer
300
views
Parallel Caps as a Bipolar (twin polar in combination)
So, I saw a similar question about 2 caps in series to make a bipolar.
Lets assume polar electrolytics
I pretty much "get" electronics and build stuff - it works as I expect mostly.
I have ...
4
votes
1
answer
118
views
Generate +/- voltage outputs using two boost converters?
I am working on a project to power some audio equipment that requires +/- 15V DC. Output current load is about 250mA, maximum. I am wondering if there’s any reason I couldn’t create this using two ...
- 51
0
votes
1
answer
72
views
How do I compute the gain on this differential amplifier (in an open loop)?
Hello! I've got this project due for a college course, and the teacher has reviewed my work and said that it is within specification, but he asked me to compute the gain the good old fashioned way ...
- 21
0
votes
1
answer
845
views
What voltage or node are the BJT substrates connected to in a bipolar process opamp IC?
I've been recently experimenting with converting transistor-level SPICE models of ICs into subcircuits. One thing I try to keep consistent with my subcircuits is that they remain floating; i.e. no ...
- 5,469
4
votes
4
answers
995
views
Why are bipolar transistors used for switching applications?
I noticed that many sites targeted at hobbyists recommend bipolar transistors (mostly NPN) to switch things on and off. Bipolar transistors definitely have their purposes especially in analog circuits,...
- 439
1
vote
1
answer
230
views
How does bipolar line coding such as AMI work with medium like fiber optics
We know that in bipolar encoding (sometimes called multilevel binary), there are three voltage levels: positive, negative, and zero. The voltage level for one data element is at zero, while the ...
- 255