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Questions tagged [negative]

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72 views

adding an antenna to a toy PCB, where can I ground it? is the negative battery cable ok?

I want to replace the antenna on my toy quadcopter with a better one, to improve reception. On toy quadcopters the antenna is just a simple wire soldered to the quadcopter circuit board (with no ...
0
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0answers
75 views

Negative voltage supply

I've been trying to make a active load that would use a very small resistor, around 10mOhm as a shunt resistor. I've figured out how to make it, it's a common circuit, however since I need to use ...
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1answer
29 views

Get negative control voltage for a AS3310 chip

I'm trying to use a AS3310 chip to generate an envelope from a trigger/gate signal. The AS3310 expects for the ADR (attack/decay/release) control voltage 0 to -5V - for the S (Sustain) 0 to +5V I ...
0
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1answer
114 views

Designing two stage CE amplifier with negative feedback [closed]

I'm trying to design two stage ce amplifier with negative feedback using 2n2222 transistors. The circuit must have certain voltage gain, Rin, Rout, Vcc, low and high frequency filter. This is the ...
0
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1answer
74 views

Op amp with feedback

simulate this circuit – Schematic created using CircuitLab How to calculate Iout(current flowing through RL) of this circuit? All Resistors are of same value except the load resistor. Let the ...
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0answers
87 views

Magic Eye Tuning Tube Variable Negative Voltage

I am thinking about several applications of magic eye tuning tubes as display pieces and had a question about their operation. I have attached a sample circuit from a datasheet for an EM84 tube. I ...
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2answers
111 views

Negative gate SCR

I've accidentally supplied the gate of an high power phase control thyristor (Vdrm=5200V and It(rms)=6500A) with a negative current (about two times the trigger current and four times the trigger ...
1
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2answers
104 views

Operational amplifier and negative feedback

Let's consider an op-amp. In every book I've read till now, it is said that if we have: negative feedback finite output then we have: Vout = A * (v2 - v1) --> (v2 - v1) = Vout / A If A is very ...
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1answer
102 views

What defines the sign of transistor rating values?

Here for example I have attached excerpts from two general purpose PNP transistor datasheets. One of them has negative values, other one positive. I would like to understand what defines these values ...
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1answer
78 views

LED indicators for 2 Positive voltages and 1 Negative

I have a seemingly simple question but I am getting stumped. I have a power supply providing +12v +5v GND and -12v. I would like to have an LED for each input voltage showing that they are working ...
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2answers
147 views

Generate negative reference voltage

In my current design, I need to include force measurement. A301 sensor is selected for this. Now, in order to be able to have analog voltage proportional to the force applied, I need to have negative ...
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1answer
256 views

negative binary representation and 4 bit BCD represenation are similar

While representing negative numbers in binary we use MSB as sign indication.In BCD we use 4 bits to represent numbers 8-15. How does a device(ex:computer) decide whether its a negative number or a ...
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1answer
274 views

Applying negative voltage to CMOS chips

I have a situation where it's possible a negative voltage may appear on the power supply rails driving CMOS chips. The negative voltage will be very limited in current, fed through a resistor. The ...
0
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1answer
49 views

Calculating power supply current output

I have a 15V power supply powering 2 Dc/dc converters that are the same. The converters are connected so that the outputs are 10V and -10V (the - terminal of the 10V converter is tied to the + ...
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0answers
91 views

Battery life and negative current

I am working on a battery powered project. With a multimeter I've been measuring current on the "positive" side of a module and observe 5μA. However I thought to measure the "negative" side and was ...
1
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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) ...
0
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1answer
101 views

Function Generator - Signal without Neg or Gnd reference

I have a new PC based function generator (very cheap), and an old BK Precision function generator. The old BK Precision can output a signal without the ground or negative reference lead from the BNC ...
1
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2answers
215 views

Inverting Op-Amp Circuit Problem

I am trying solve the question shown in the picture below (I am assuming the switch is down in the picture, I can't tell) The equation that I am using is Vout/Vin = - Rf/Rin because there is ...
2
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2answers
644 views

How does using negative feedback in biasing stabilize the beta of a BJT?

As far as I know the only reason beta is not reliable because it is temperature dependent. I have seen some diagrams about biasing to obtain stable beta. I read the negative feedback provides this ...
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3answers
8k views

When do I connect to negative terminal or ground?

Easy question (or at least I think). I've installed a siren in my vehicle which calls to pull power direct from the 12 volt battery. I currently have the circuit completed by connecting to the ...
2
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2answers
243 views

Analysis of Negative Input Resistance Op Amp

simulate this circuit – Schematic created using CircuitLab I'm having a difficult time analyzing the circuit shown and would appreciate some help. I'm just curious in order to get better at op ...
0
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3answers
92 views

Connection of dusl 12v NiCd battery packs [closed]

I have the 12v battery (it is actually 10 Ni-Cads in series), and, of course, it has a red wire coming from "+" and a black wire coming from "-". However, on the schematic I am confused about whether ...
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2answers
3k views

Where is the positive and negative on an antenna?

What I am wondering is how to build an antenna. Upon unscrewing my telescopic antenna from it's base, I see only a metal screw base, nothing more. The F Connector has a positive and negative (or ...
0
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1answer
251 views

Negative charge pump problem

I have an 18V 1.5A mains transformer (outputs around 30V peak with no load at 50Hz) followed by a full-bridge rectifier and a filter capacitor: (there would be a schematic here if SE allowed me more ...
2
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3answers
3k views

How does this Push-Pull amplifier work?

I'm reading about op-amp circuits that use negative feedback from this article (question no.19). What confuses me is that the negative feedback for the Op-amp (which is being used to reduce ...
0
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2answers
202 views

Why is it not possible to find pnp bipolar and n channel mosfet transistor arrays in IC package?

I use a lot of 2N3906 pnp bipolar transistors and 2N7002 n channel mosfets on my pcb. I was suprised to see that there are no cheap and commonly available IC packages for these common transistors as ...
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2answers
611 views

LM317 output voltage to 0 V with transformerless negative voltage created through a buck converter

I try to construct a shut down pin or a feature which can set the output of LM317 or LM78XX with negative voltage that is created through a transformerless buck converter. A buck converter having ...
0
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1answer
556 views

How to connect earthed metal chassis to DC ground?

I have around 12 purely DC PCBs inside a metal case. Each has a MCU which connects to the main controller PCB with SPI or I2C. Each is powered by one shared ATX PSU which also sits inside of the case. ...
0
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1answer
269 views

Using negative clock edge in phsical design

In Verilog, is it ok to use negedge of clock. Can a memory element be triggered at the negedge of clock? How robust will be the design practically in the chip?
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2answers
1k views

Negative level shifter

I need to connect two circuits that use different PSU voltages. The first is a microcontroller clock generator, it outputs a clock 0V to 3.3V at 150KHz as maximum freq. I need to connect this clock ...
0
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1answer
190 views

0-5v to 5 to 0 v analog level conveter

I have a HBLED driver that for some reason, uses a 5V-0V linear control voltage. The driver has the LED OFF at 5V and full on a 0V. Id like to be able to use the drivers with a 0v-5v signal. Im ...
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3answers
2k views

How to generate positive and negative square wave with frequency of 1Mhz?

im planning to generate a square wave with positive and negative voltage, so basically, i create a 1Mhz square wave from a microcontroller, and send the output to a circuit which will convert the 0-5V ...
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2answers
289 views

Is there a real difference between the voltages produced at the negative and positive ranges of the AC sine wave?

This a general electrical question. When reviewing the AC sin wave, we note that the curvature of the wave fluctuates between a positive and negative 180 degree range. Is there a real difference ...
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2answers
47 views

Do 2 conductors (1 grounded via resistor) reach equipotential, before surplus electrons drain to earth?

Case I: a negative conductor makes contact with a neutral conductor. Negative donates some electrons to neutral, until there is 0 potential difference. Then they both are slightly negative. This ...
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1answer
685 views

converting 0V - 10V to -5V - 5V

i am an absolute novice when it comes to electronics. i am looking for an (ideally passive) circuit of some sort, that converts voltages from 0V - 10V to -5V to 5V. i'd be gracious for any hint or ...
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2answers
86 views

Can we produce more negative voltage from a less negative voltage source? (say -8 volts from -3 volts supply)

I was thinking about the concept of negative voltage when I came across this question. I understand that negative voltage means voltage below a certain threshold, say ground. So, can we use simple ...
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3answers
252 views

Negative voltage source (-0.55V)

I am using one of the IC in my project and it needs -0.55V with maximum of 220mA. I will appreciate your recommendation for this solution,since i search a lot but unable to find any valid solution for ...
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3answers
481 views

Implement AND gate multiple ways (positive & negative logic)

Could somebody explain to me how how negative and positive logic works? If I have an AND gate the truth table will be x y z 0 0 0 0 1 0 1 0 0 1 1 1 If I wanted ...
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4answers
2k views

negative current for discharging capacitor

So I was trying to derive the exponential decay equation for a discharging capacitor and realised that I would only get the correct answer if I used a negative current, that is to say the direction of ...
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2answers
487 views

Input stage of a current mirror circuit

I'm trying to understand current mirror circuits and I've been reading this article. I'm unable to understand the input part of the circuit where the author says "Producing the opposite where the ...
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2answers
655 views

altium cannot change hole color

I am trying to print pdf of negative artwok in the altium. I am adding full fill on the board different layer. Then change layer color( make black and white ) through Page Setup>Advanced>Preferences. ...
3
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2answers
274 views

Ground connections and symbols in schematics: should they be separate or connected?

I'm new to this world of electronics and I'm trying to make a fuzz face pedal. I'm not comfortable with the notion and symbol of ground connections. Do I have to connect all the ground points to the ...
3
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4answers
825 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
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1answer
162 views

Negative Voltage Ccfl Inverter from AC Adapter

I have a CXA M10M-L ccfl inverter and I need negative voltage from its output, for anode ground scheme of a photomultiplier tube. I am confused because most discussions of this topic use batteries to ...
2
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3answers
420 views

Get -50V to 50V range from battery output

I have the following problem: on the system which is battery-powered(4S1P Li-ion battery, 14.8V) I need to create outputs from -50V to 50V. The system has microcontroller on-board. I am baffled on ...
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2answers
357 views

Double polarity pulse with one single power source and virtual spdt switch

I have a problem in the design or my circuit. I need send data at a maxixum bitrate of 12000 bits /second. The high value should be +12v and the low value should be -12v providing at least 35mA of ...
0
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3answers
537 views

If negative input ==> 0 V Otherwise, input voltage

I am struggling, and I would like to know how I can make a circuit that holds the following conditions: If the input voltage is negative, then the output should be zero volts. If the input voltage is ...
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1answer
2k views

Negative Artwork in Altium

I wanted to print the negative artwork from a PCB that I've designed. The problem is that I couldn't find that option in Altium Designer. I found that I can create a solid layer and then play with the ...
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5answers
9k views

7912 Voltage Regulator [closed]

So my senior project is due Thursday and because of my extreme wits and knowledge I accidentally connected A 7912 Voltage regulator the incorrect way because I was unwary of the different pin-out. I ...
3
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1answer
341 views

Single voltage replacement for 741 opamp

I am working on a project that recreates the cassette-in port on an Apple II for use in an Apple IIGS. The original circuit used the LM741. The location where I am interfacing my circuit only has +5V ...