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Questions tagged [reverse]

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0
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0answers
30 views

Simple Animatronic - slow repeating/reciprocal motion for a window display

I am trying to rig a contraption to pull a model hot air balloon back and forth along a curved horizontal track. Its motion is both horizontal (6’) and vertical. I have built the track and rigged the ...
-1
votes
3answers
46 views

Reverse Current Protection using two PMOS in back to back configuration

I am working on a circuit that needs reverse current protection. Back to back mosfet configuration has been suggested by many people, and it seems to make sense at the beginning. But after I built my ...
0
votes
1answer
36 views

making a photodiode module

I am trying to do stimulated Raman scattering microscopy. In this experiment two pulsed laser beams are used . The wavelength of these two laser beams is tuned to match a specific Raman frequency of ...
0
votes
1answer
51 views

Continuity testing - Why does swapping DMM probes give differing results?

Continuity query - Can anyone explain this? Circuit is a simple 12v DC, wired as follows -battery pos to bulb to spst switch back to battery earth. Testing with DMM in the dedicated audible ...
0
votes
1answer
71 views

Where would Icbo flow through and would it cause thermal runaway?

I was reading this page about thermal run away. And it mentions: Due to increase in the temperature of collector junction, Ico will increase, Vbe will decrease. But for Ico to increase Ic and ...
4
votes
1answer
204 views

help understanding this reverse polarity protection circuit

Going through LT4363 evaluation kit DC2062A-B (schematic here), I came across a reverse protection circuitry that protects downstream components from reverse transients and reverse DC voltage: In ...
6
votes
2answers
240 views

Reverse voltage protection for Analog Devices’ family of protection controllers

After going through several datasheets for devices from "Analog Devices’ family of high voltage surge stoppers, overvoltage protection, overcurrent protection, and circuit breaker ICs", I found that ...
0
votes
1answer
125 views

Diode reverse current

If I apply an current source into the the cathode of a diode (current flow into cathode), what can possibly happen to the diode. For the cuicuit below, when the FET is OFF, how does the battery ...
5
votes
1answer
538 views

Replacing two LEDs with a 2-pin, bicolor LED, using a circuit that reverses polarity based on two inputs

I'm working with a commercially available circuit that can optionally be configured to disable its internal LEDs and use two external LEDs. This post discusses the use of external LEDs. One LED or the ...
0
votes
1answer
57 views

Reverse engineering, doubt with value of capacitor

I want to do reverse engineering of this module (Digital Microphone) First of all I tried to get the schematics from the supplier but they don't have them. Finally I starting unsolder each capacitor,...
0
votes
1answer
49 views

Running a DC motor through a bicycle and charging a battery [closed]

I am running a DC motor through a bicycle and charging a battery. Does battery gets charged while pedaling in both the directions? I observed from voltmeter one is negative voltage. I am novice in ...
0
votes
4answers
74 views

Reverse Polarity Protection, External Circuit

I'm trying to figure the best way to protect the external circuit from a short if a user mistakenly connects the sensor in the wrong polarity. I use a green object in the diagram to represent the ...
0
votes
1answer
549 views

Need help reversing the rotation my motor

I'm pretty new at this. I was able to salvage the motor of a washing machine. How will I know if I can reverse the rotation of it? And how will I be able to reverse it if it does? Also how will I ...
1
vote
1answer
144 views

Cannot find “reverse saturation current” of base-emitter junction in the data-sheet

Regarding the reverse saturation current \$I_{ES}\$ aka \$ I_{EO}\$ of an NPN transistor, according to Ebers–Moll Model: \$I_E = I_{ES} (e^{V_{BE}/V_T} -1) -\alpha_RI_{CS}(e^{V_{BC}/V_T}-1)\$ ...
-3
votes
4answers
167 views

How do I reverse-bias a resistor?

We all know that a photo diode can be used as a light detector and as a light emitter (although the way that it's built will usually make it specialized to prioritize one application over the other); ...
3
votes
2answers
578 views

Proper way to demonstrate reverse recovery time of a diode using SPICE simulation

After encountering a nice example from an answer of this question, I wanted to simulate the same circuit in LTspice to compare the reverse recovery times of two diodes 1N4148 and 1N4007 by a 5V ...
1
vote
2answers
312 views

Power supply 0-30 volt reverse voltage protection

I have made a bench power supply that can erogate 0-30 volt and 0-2 A. Now, how can i protect my bench power supply from reversed voltage applied to it's output? Typical p or n mosfet circuit dosent ...
0
votes
3answers
60 views

Why current appears at reverse bias?

I am simulating time-domain graphs of a Schottky diode model. I am expecting ~zero current at the negative half cycle. But I am seeing negative current. It's only about 3mA, but based on I-V curve, ...
0
votes
5answers
72 views

Proper name for “a switch-over time-delay relay”

I have a joystick wired to a relay that spins a motor either one way or the other way. The problem is that I need to enforce a small "dead-time" when the user pushes the joystick quickly from one ...
1
vote
0answers
52 views

Apply positive and negative voltage to component using single power supply [duplicate]

I have an electromagnet and a 12V power supply. I would like to apply +12V to the electromagnet at some times and -12V at other times. My current thought is to use four transistors (two NPN, two PNP) ...
1
vote
1answer
108 views

Diode connection in reverse bias

Please help. In reverse bias we say the negative terminal of the battery attracts holes of the p-type hence depletion zone becomes bigger. Why don't electrons from the negative side of the battery ...
0
votes
2answers
2k views

A confusion about the formula for transistor Vbe Ic characterisitcs

Below is NPN BJT transistor Vbe Ic characteristics and the formula: Many texts approximate this equation as: Ic = Is*e^(Vbe/Ut) and following this they say when Vbe=0, Ic becomes equal to Is. ...
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votes
1answer
65 views

when given voltage, reverse voltage according to scale [closed]

I am given a DC line with a variable voltage along a set scale: let's say 0-10V. I would like to send an output DC line with a voltage reversed along that scale. For example: 10 Volts in becomes 0 ...
2
votes
1answer
412 views

Why does the reverse saturation current not vary with the reverse voltage?

I can understand that in the depletion region of a diode more covalent bonds are broken(more electrons goes to conduction band) with more temperature hence we say that the reverse saturation current ...
0
votes
1answer
157 views

“Inverting a switch”

I have a scooter ignition lock that i got from ebay and i was planning on retrofitting it on a 1980 motorcycle. The thing that i need to make this work is that the ignition lock needs to be closed (...
0
votes
1answer
116 views

Can I drive and reverse this motor with an ESC?

I've just ordered this motor, which I want to drive and reverse using my Raspberry Pi. I've successfully used an H-bridge to drive and reverse a brushed DC motor before, but for this motor I think I ...
0
votes
2answers
391 views

Reverse current blocking on switching regulator

I was thinking what is the best solution to add a reverse current blocking on switching regulator. My first thought was to look for an ideal diode circuit but all of them were too much expensive. The ...
0
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0answers
688 views

Inverse active mode of BJT

Here is my task: Find input voltage Vul and base voltage of T1, so that T1 enters full reverse active mode. Explain. Voltage base-emitter of BJT (when it conducts) is 0.7V, voltage base-emitter in ...
0
votes
1answer
179 views

Why do some logic gate chips have a reversed pin layout?

I am using some logic chips by Texas Instruments, namely SN74HC02N, SN74HC04N, SN74HC32N and others. When I connected them in my circuit, the SN74HC02N NOR-gate didn't work as expected, so I searched ...
-1
votes
1answer
252 views

What does a commutator do in dc machines?

It's my exam and in need help I am sure it's reversers current and I don't know my english lecturer say it's no it's provides current I need help please
0
votes
1answer
2k views

How is this synchronous AC gear motor being reversed?

I just disassembled the shifter assembly in a washing machine. It uses a synchronous 120VAC gear motor. The motor says "CW/CCW Z.P." It has two leads for the AC power and no other inputs. I ...
0
votes
2answers
484 views

Short circuit problem (batteries getting HOT) within circuit

So I am making a circuit with a simple 12v dc motor in series with an NO microswitch and on off switch conntected to a dpdt switch to reverse the polarity of the motor. The first issue I had was to ...
-2
votes
1answer
550 views

Micro switch off in forward and on in backward

I request some knowledge regarding a circuit I am building. Basic I have a circuit connected to a dc 12v motor and a dpdt switch to reverse the polarity of the motor and a variable potentiometer , I ...
1
vote
1answer
92 views

varistor with reverse operaton

Varistors are known to use for over-voltage protection, as they have high electrical resistance at low voltage which decreases as the voltage is raised.(wikipedia). But is there any electrical ...
0
votes
1answer
39 views

Can I reverse this motor?

For a pet project I want to run a motor and also be able to reverse the direction. I found this motor and pasted the information table below. As far as I know a DC motor needs to be brushed for it to ...
2
votes
3answers
3k views

Does reversing polarity in AC damage the equipment? (Sonoff Wifi Switch) [closed]

Firstly, I am a beginner. Excuse me if this is a dumb question. I have ordered a Wi-Fi switch named Sonoff. I have a doubt whether the device will work if the polarity is reversed or will it get ...
0
votes
2answers
539 views

Help decoding bus signalling

I'm trying to decode a RS485 bus from an alarm system. If I connect it to a computer on baud 3600 then I receive ASCII strings which match what is being shown on the alarm panel; however, when I look ...
0
votes
1answer
3k views

How to control the output voltage for the different types of the dc generator?

Generally DC generators are classified according to the ways of excitation of their fields. There are three methods of excitation. Field coils excited by permanent magnets – Permanent magnet DC ...
0
votes
3answers
584 views

Will a simple chinese step-up converter convert down if used in reverse? [closed]

Let's say I have this converter (ebay link): It accepts 10-60 DC volts as input and outputs 12-80 DC volts. What I'm asking is if it is possible for me to INPUT 60-70 Volts onto its OUTPUT pins and ...
1
vote
0answers
1k views

How can I add N channel MOSFET for reverse polarity protection?

I would like to add a reverse polarity protection circuit to protect my circuit from reverse polarity. I tried to use following circuit at this link With NMOS FET, I have a little problem. If the ...
0
votes
1answer
1k views

Using a 3 phase step down transformer in reverse

I have a 30kVA transformer with primary 480V delta to 208V Wye secondary. I am relocating to a building that has 208 service, and would like to use the above transformer in reverse, so that I can run ...
2
votes
1answer
5k views

Reversing direction of an AC universal motor

The problem: I have a table saw motor I am trying to use in a jointer and need it to spin in the opposite direction (permanently). I have had trouble finding an answer that I am reasonably sure ...
1
vote
1answer
224 views

Output of 4.8V due to reverse polarity series schottky diode?

I was reading through the Data Sheet for the Photon, an IoT dev board: https://docs.particle.io/datasheets/photon-datasheet/ and under the Power section it says: When the Photon is powered via the ...
3
votes
4answers
822 views

How to generate a -24V signal

I have to interface a specific motor, it has a weird driving board, I was in contact with the technical team from the manufacturer, and they told me that I have to send a -24V on a pin to allow it to ...
0
votes
4answers
357 views

Rapid Reverse polarity

This is the circuit for reverse voltage protection, R2 is the load of a motor. The problem is that there is a test where the changing of polarity is very fast ( <5ms) and the MOS burns. Power ...
2
votes
1answer
812 views

Reversing a throttle position sensor signal

I'm very new to electronics, but I'm trying to reverse the signal coming from a throttle position sensor as well as change the voltage range slightly. The throttle position sensor output signal range ...
3
votes
1answer
80 views

Help identifying modulation scheme

I'm trying to identify the following modulation scheme being used to transmit a infrared code. It looks like manchester, but there's some gaps where there's no transitions. The code being ...