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21 views

ZXM61N03FTA as a replacement for Si1308EDL

I'm working on a e-Paper display driver. The reference design uses Si1308EDL as part of the boost converter. I'm sourcing the components from LCSC, but unfortunately Si1308EDL is not in their stock. I ...
0
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0answers
53 views

Would this shift register schematic avoid master/slave if I extended it to four billion bits? [duplicate]

simulate this circuit – Schematic created using CircuitLab The basic data structure for the machine I want to build is a shift register. Quite some time back someone told me that if I could ...
0
votes
1answer
35 views

How do I solve the input resistance of this BJT and MOSFET in series?

This is a sedra-smith microelectronics excercise question for which I can not find the answer and I hoped for perhaps a solution here?
1
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3answers
53 views

N-Channel Mosfet or NPN transistor for Low Power PWM Application

simulate this circuit – Schematic created using CircuitLab LED: 2.05V @ 350mA 5-6 Ohm Resistor for current regulation Hi, currently designing a circuit that controls a LED using a PWM logic ...
0
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0answers
130 views

IRF7821: is one of them fake?

Left looks like genuine (logo), right looks like fake. Is it, really? Edit: this part is expected to be IRF7821.
0
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0answers
43 views

Why does an ISFET need a reference electrode?

I'm trying to understand why an ISFET needs a reference electrode. I have looked up several answers online but still dont understand. I have drawn out the doping, a MOSFET and the ISFET: In my mind, ...
0
votes
1answer
28 views

Finding node voltages in a MOSFET circuit

simulate this circuit – Schematic created using CircuitLab Considering Vdd=5v I want to calculate the node voltages at P,Q and R.
0
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1answer
82 views

Equivalent resistance in this mosfet circuit

simulate this circuit – Schematic created using CircuitLab I have 3 NMOS are connected as shown above. I need to calculate equivalent resistance as seen by the capacitor so that I am able to ...
0
votes
2answers
50 views

Voltage controlled connection of two signals that are at higher voltage than the control voltage

Given are two signals A and B. I want to control the connection between them by a signal C. However, signal C is a logic signal with a voltage of 3.3V for high and 0V for low whereas signals A and B ...
0
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1answer
49 views

What transistor setup to use for level shifting to create a logic ENABLE signal (for DC-DC converter module)

I want to create an ENABLE signal driving a Murata OKI-T/3-W32P-C DC-DC converter, where the P stands for Positive Polarity of the On/Off Control line: the line has an internal pull-up, which means ...
0
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2answers
71 views

Can Vds ever becomes negative in mosfet?

Due to the symmetry in mosfet, source and drain are interchangeable. So we define the source of nmos is the terminal with the lower voltage. So if we force Vds to become negative the drain and source ...
2
votes
1answer
106 views

NMOS bootstrapping without an IC

Like the title says, I was trying to bootstrap a high-side NMOS. After some googling I found this video https://youtu.be/zcQV_ZpK1W8 which helped me a lot except for one thing which I cannot ...
1
vote
1answer
128 views

CD4011BPWR Button Press Logic NAND IC

During testing on my pcb I am running into a couple of problems the first issue is with either my momentary switch or my MOSFET Q4 – PMV30XPEA. For my switch design, I have implemented Fig. 5 on ...
0
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2answers
104 views

Switching a fan on/off based on an LEDs current

I have a small TV box which needs a fan because it overheats causing the cpu to throttle. I would like to have the fan turn on when the box is on, and turn off when the box is off. Unfortunately, the ...
0
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0answers
52 views

MOSFET input and output capacitances

I need some explanations about the MOSFET parasitic capacitances. Precisely, what I studied is that there are those parasitic capacitances: But generally in digital electronics texts I see that they ...
2
votes
4answers
166 views

Why reverse connected MOSFET start to turn on at Vgs<Vth?

The circuit shown below is implemented using two AO3400 N-MOSFETs. AO4300 datasheet here. The right-hand MOSFET is connected with normal polarity (Vds is positive), while the left-hand MOSFET is ...
4
votes
2answers
553 views

Is MOSFET active device?

The V-I characteristics of MOSFET lies in the first and third quadrant. Therefore it should be passive device acc to me. But I have read that it is an active device. Can somebody tell what is wrong ...
0
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2answers
53 views

CMOS inverter propagation delay

Let's consider a CMOS inverter. It is known that its propagation delay depends on supply voltage (VDD) and on output parasitic capacitance Cout (which is due both to its transistors' output intrinsic ...
0
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1answer
67 views

Pass Transistor: discharging of the capacitance

let's consider this pass transistor logic: Let's assume that the MOSFET is always active (CK = high for a N-MOSFET). Now, immagine that at the beginning Vin = 10V and Vx = 0: the capacitance Cx will ...
1
vote
1answer
47 views

When to use P-Type current source(using pMOS) and when to use N-type current Source(nMOS)?

I am referring to Prof. Behzad Razavi Lecture https://www.youtube.com/watch?v=GAvZLyii3aw&list=PLiDoPUX9nLkIw9EnIv_3K19wlcyJ6msYd&index=2 (Minutes 19-26) Prof. says to use nMOS when we draw ...
0
votes
1answer
113 views

Using transistors to switch 12v from a 3.3v signal

I'm a pretty accomplished programmer, but working directly with electricity is giving me the fits. I'm trying to replicate a design that switches a 12v/300ma solenoid based on a GPIO signal from a ...
0
votes
2answers
51 views

Inverted high impedance / pull down circuit

I'm devising a circuit to control the shutdown input on an integrated circuit. The IC accepts a high impedance input (can't be pulled to any voltage) to enable operation, or it can be pulled down to ...
0
votes
0answers
108 views

DC boost converter output voltage problem when load is connected

I have successfully finished one part of the DC converter. Now I came across a certain problem which I can't solve myself. When I didn't connect a load to the output of the dc converter, there was ...
0
votes
0answers
30 views

Test circuits for testing input and output capacitance of an NMOS spice model?

As the title states, I'm having trouble finding resources online for confirming the capacitances of an N-MOS spice model. If there are any resources someone could point me to to learn more or test ...
1
vote
2answers
144 views

Complementary transistor pair with a bipolar transistor and a MOSFET

I own a set of Soviet IN-14 Nixie tubes and I would like to use them to make a vintage clock. I found this example schematic of a "Nixie clock": I don't understand what is the purpose of using a ...
1
vote
1answer
104 views

Normally closed mosfet circuit

I'm designing a battery charging circuit for a portable device. Conceptually it looks lik so: simulate this circuit – Schematic created using CircuitLab As a safety function, the circuit can ...
1
vote
0answers
36 views

How does a FinFET reduce subthreshold swing comparing to a regular MOSFET?

I get that a lower subthreshold swing means there is a smaller current when the transistor is off and that's one of the reasons that finFET is preffered to MOSFET. But I don't understand how it does ...
2
votes
2answers
199 views

Class A Audio Amp - Improving Efficiency With A Mosfet CCS

I'm designing a class A audio amplifier but am struggling with the efficiency of my circuit. I know of 'push-pull' Class A designs, but only want to use a single output mosfet. I would like to hit a ...
0
votes
1answer
131 views

Class A amplifier with preamp design

I am currently working on a class A audio amplifier designed to work with line in voltage (about -400mv to +400mv). I plan on using an IRFP240 for the mosfet but am undecided on the transistor stage. ...
0
votes
0answers
107 views

Effects of changing the width of transistors

Looking at the figure attached, I want to understand how does increasing x, affect the noise margin of the gate [i.e. (High noise margin) & (Low Noise Margin)]? Also, how does increasing x affect ...
1
vote
1answer
37 views

2-time constant (On + decay) timer circuit

Required is a timer circuit to switch on an LED with 2 time constants, when a switch is depressed as follows: when switch is closed, light an LED 10 ~ 20mA when switch is opened again, keep the LED ...
1
vote
3answers
123 views

5V digital output to 24V

I'm sure it is a simple solution but I am new to this so please take it easy. I need to come up with something to convert a 5V digital output signal from a USB-1608G DAQ device with DIO to 24V ...
2
votes
1answer
167 views

What mosfet do I use in induction heater?

I have been building an induction heater based off this schematic. I have tried using irfp250m mosfets. Works like a charm. But whenever I put a too big piece of iron inside the coil, the mosfets soon ...
0
votes
1answer
44 views

NMOS to NPN Circuit Analysis

I am attempting to us a voltage shut off switch with some pre-existing hardware. I do not understand transistors well enough yet and am looking for clarification. I desire for V2 to be able to go to ...
0
votes
1answer
61 views

What is the advantage of concatenating two nMOSFETs M1,M2 with Source of M1 connected to Gate of M2?

I am trying to understand the circuit in the figure here : I hope I analyzed correctly its gain (for small AC signal). My small-AC-signal-circuit is attached in the bottom of this post). However, I ...
1
vote
1answer
84 views

Circuit to switch negative to negative, or positive to positive connection

I am wondering if there is a negative to negative (and/or positive to positive) switch. I know mechanical relays work, but I need an electronic way of doing it. Is there a transistor that functions ...
0
votes
1answer
76 views

Mosfet pinchoff, why the n-channel moves towards source?

Suppose we have an NMOS transistor with \$V_{GS}\$ > \$V_T\$. When \$V_{DS}\$ is 0, the channel depth is uniform along the transistor. However, when we increase \$V_{DS}\$, the channel becomes deeper ...
4
votes
1answer
108 views

MOSFET switching on

I have a doubt. Consider an N-MOSFET: which is the voltage that can switch on it? The voltage between Gate and? Sometimes I read "between Gate and Bulk", sometimes "between Gate and Source", sometimes ...
-1
votes
2answers
53 views

trying to figure out the differences between the six transistors provided by the schematic tool [closed]

My background consists of a BS in Computer Science and an MS in Computer Science and Engineering, both from the University of Washington. My MS consisted mostly in the very high level design of a ...
0
votes
1answer
58 views

Why is SLEW RATE in nMOS amplifiers worst when the output is going from LOW to HIGH?

And, of course, why in pMOS amps the SR is worst in the other case (output going from HIGH to LOW).
0
votes
2answers
192 views

Control 12V DC via MOSFET and normal transistor

I made this schema and I want to ask, how transistor control MOSFET. What that s8050 transistor do with the IRFZ44N MOSFET. Please, help.
0
votes
1answer
50 views

How can I detect that a ZVD-style 'backpower protection circuit' is operating correctly?

I'm designing a circuit that needs a 'backpower protection circuit', similar to what the Raspberry Pi HATs use. This is meant to block voltage from the secondary board when the primary board is ...
0
votes
1answer
58 views

Field effect transistors

Assume we have a field effect transistor.We connect the source terminal to the anode of a battery and the drain terminal to the cathode of a battery.We connect the gate terminal to cathode of a ...
1
vote
2answers
64 views

When is a Gate potential zero?

I have this fairly simple NMOS and it is mentioned that I can determine the Source current \$I_3\$ with the formula \$ I_3 = \frac{K}{2}(V_{GS} - V_{th})^2 \$. Here they equalize Gate Source Voltage \...
0
votes
1answer
78 views

NMOS High Side switch circuit solving

I'm trying to get my head around the circuit theory behind the high side NMOS switch, here is the shematics: My question is not about whether this is a good or a bad way to make a high side switch (I ...
1
vote
3answers
131 views

Controling Mosfet by 3,3V Raspberry Pi GPIO Pin

So I'm currently working on a project where I need an IR camera with two IR Leds attached to it. The camera looks something like this: https://rads.stackoverflow.com/amzn/click/com/B01ICLLOZ8 These ...
0
votes
2answers
515 views

Drive 12V Automotive Relay from 3.3v ESP32

I am working on a project to start a vehicle using Automotive Relays. And I am following this circuit in the tutorial to do so. Everything works fine on Arduino UNO. But I want to use ESP32 of this ...
0
votes
0answers
30 views

Replacement of DMP2215L P-Channel MOSFET with AO3401 from Alpha & Omega

I want to replace a faulty Diodes DMP2215L SOT23 p-channel MOSFET https://www.diodes.com/assets/Datasheets/ds31125.pdf with the p-channel AO3401 MOSFET from Alpha & Omega http://www.aosmd.com/pdfs/...
0
votes
2answers
107 views

LED driven by MOSFET is dim

I have this schematic: I had to replace T1 transistor with a MOSFET (because D4 on an ESP8266 has to be high at boot time and the transistor reduces the pin voltage, so the ESP doesn't boot - see my ...
2
votes
4answers
1k views

What kind of transistor turns on with 0.2 volts?

I need a circuit to turn on a LED with 0.2 volts. I want to do it with a transistor as a switch. What kind of transistor will turn on at this voltage?