Questions tagged [floating]

A voltage that is not connected by any conducting path (including resistors) to ground or the key voltage reference point.

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2answers
472 views

Floating voltage on metal shelf

I just setup a pepper seed starting shelf using a metal shelf from a Swedish furniture outlet. The shelf has no electrical contact with the 5x T8 bulbs which are hanging on plastic zip ties. The T8 ...
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1answer
77 views

Using a DAQ with a programmable power supply floating input

I have a programmable power supply (Sorensen DCR300-16T) that requires a floating programming voltage. From the manual: (3.9.1) In selecting a signal source, the following should be considered: ...
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2answers
317 views

Noise pickup in fully floating circuit

I'm using an ac coupled noise matching transformer to measure the voltage noise of a low ohmic sample as a function of bias current. The complete circuit is in an enshielded enclosure. When the ...
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5answers
1k views

How is the input not floating when there is a pull-down resistor? [duplicate]

I am wondering why the input to D2 will not be floating when the switch is open. If the switch is open, wouldn't it act like a mini antenna and provide a random input to the D2 pin?
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1answer
174 views

What are the risks of running a floating ground through insulated wire underground?

I've created a circuit that is powered with a floating ground off of a transformer. I'd like to count pulses from a meter by having the meter complete the floating ground side of the circuit but I'm ...
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1answer
1k views

Connecting Two Grounds Together

I'm trying to understand what would happen when connecting two grounds from diffident power supplies together. A more in depth explanation of what I'm trying to accomplish is here: Connect Arduino to ...
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3answers
582 views

Understanding microcontroller ADC input pins (atmega328)

If I set up the ADC on the ATmega328 to read from a certain ADC pin, what state is the ...
6
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4answers
2k views

Why would you need a floating signal on a board?

I read the following from a book titled "An Embedded Software Primer" by David E. Simon. (23rd print Nov/2014 - Page 16) If no part on the circuit is driving a signal, then that signal is said to ...
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1answer
146 views

Floating inputs and Vref on a voltage subtractor (PWM to Gate converter)

A little background: I'm trying to extract a gate signal from someone else's circuit (ckt1) so that I can synchronize events in my design (ckt2) to a sequential trigger in theirs. First problem is I ...
2
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1answer
1k views

Design for a balanced (positive and negative) HV DC regulator

I'm trying to design a high voltage DC regulator for driving a PZT that will provide both +200 and -200 V outputs referenced to ground. The input is a rectified AC waveform that will provide UK mains ...
2
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1answer
732 views

How to prevent floating input for this system?

I have a simple system where a motor speed is controlled by a voltage signal via a circuit. Below represents the system where A is the voltage signal device; B is the circuit and M is the motor. The ...
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1answer
74 views

What would I expect to read from a disconnected SPI port?

I'm writing a program that reads from a SPI port. However, there's some complicated logic that controls whether the slave is physically connected to the port (if not, the lines are left floating). ...
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1answer
2k views

What to do with unused TTL and CMOS outputs?

Just about everything I've read on the Web, including on this site, say that unused TTL and CMOS outputs should be left floating. However, this TI article, Designing with Logic, states: Unused ...
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2answers
518 views

Why do we use pull up resistor with PIC?

I tried to find an appropriate answer for the question but couldn't find what I needed exactly. I found out that "Initially the output from the PIC is floating and we use the pull up resistor R7 to ...
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3answers
720 views

Are capacitors floating power supplies?

I'm struggling with the concept of floating voltages. For a grounded supply I can connect one side to an effectively infinite ground and get full power. It may vary depending on its construction, ...
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1answer
3k views

Pulling the circuit's voltage to the ground with grounded probe

When measuring a point on an isolated circuit board with my grounded oscilloscope, I fear my oscilloscope ground will pull the measured point to ground level but this has never happened, I am always ...
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2answers
1k views

2N7000 behaviour explanation

I recently bought a 2N7000 transistor and though it was a cheaper replacement MOSFET compared to the STP55NE06 as I didn't need to handle high voltages and high currents. However it acted very ...
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1answer
492 views

Why are the dimensions of a floating gate layer in a MOSFET so thick?

For a floating gate MOSFET, in order to make the control gate work you have to(generally speaking) make the oxide layer thin(~100 Angstroms) as well as the ONO(Oxygen nitride, acts as an insulator) ...
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1answer
104 views

Provoking Floating Port

I have a floating pin / port on a micro controller. I want to show that the maximum additional current from this pin is above a certain safty threshold. Can I somehow provoke the pin to draw ...
5
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1answer
542 views

What is the purpose of transistor and zener in this circuit?

simulate this circuit – Schematic created using CircuitLab (simulation will not be correct because the diodes are added just by its name.) Hello, I am a student who is not really familiar with ...
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2answers
433 views

Floating value when connecting to IC input

I'm currently having a strange issue with what I think is a 'floating' signal. The setup: I have a bank of inputs (which are connected to a resistor and LED acting as a pull-down) connected to inputs ...
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1answer
281 views

FPGA input pin internal floating

I am now occouring a FPGA pin damage problem. One of my pin is hardware connected to a 1.8V signal that will be switched on/off occasionally, while the port is not connected to any other logic gate ...
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1answer
189 views

FPGA + SRAM - floating inputs of SRAM during configuration of FPGA

I'm connecting SRAM to FPGA (Spartan 6). During configuration and during periods when FPGA will be down (for example I would like to turn off FPGA when external flash will be programmed by uC) address ...
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3answers
1k views

How to check if a DC power supply is a floating source?

Imagine a laptop power supply with 2 prongs and I'm using this as a power supply for a circuit, and the output of this circuit is an input signal Vin for a data acquisition hardware. How can I ...
11
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2answers
15k views

Floating multiple sealed lead acid batteries in parallel

I know with multiple lead-acid batteries you should really charge them separately so that one battery doesn't try and charge another and waste power. But that holds true for the main charging process....