All Questions
Tagged with 7805 voltage-regulator
40
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In which option, the diode will make the lm78xx circuit safer
This image was taken from Fairchild's datasheet on lm78xx. I have already built a working example of it, but I am still thinking about adding some additional diode protection (D1, D2). Which option ...
- 33
4
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2
answers
798
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Voltage regulator not heating up ... How?
I connected a L7805 to a water fountain that I measured to be consuming 0.1 A at 5 V to regulate power coming in from three 5 W, 12 V solar panels connected in parallel.
The regulator is not heating ...
- 41
3
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4
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893
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What are these parameters on the 7805 voltage regulator datasheet?
From the datasheet for the 7805 voltage regulator this information is available.
I have multiple questions about this information, which I haven't been able to find clear answers to on Google.
What ...
- 4,145
3
votes
3
answers
2k
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Which capacitors to use with voltage regulator IC such as 7805?
Many of the tutorials suggest to use a large smoothing capacitor (tens and even hundreds of uF) with a full wave rectifier but the datasheets of the voltage regulators and some tutorials suggest only ...
- 333
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3
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2k
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7805 voltage regulator reverse polarity
I'm working on a project for which I need to use a 7805 voltage regulator. I feed 9V to its input pin and power a 5V board with the output. However, when the board is connected to a computer, the ...
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12VAC-5VDC regulator, but L7805CV doesn't work properly
Hi everyone. I am trying to make 12VAC - 5VDC power supply. However when plugged in, voltage between L7805CV in - ground was 4V while output was 1V.
I have test 7805 separately and it works correctly ...
- 125
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votes
4
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553
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Input voltage control by resistor, is this method is correct or not?
In my application I have a requirement to switch 40V to 5V with the help of a linear voltage regulator. My load circuit consumes approx 7 to 8 mA.
Due to the unavailability of any specific model of a ...
- 43
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2
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81
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Regulated Power Supply
I am supposed to simulate this circuit (regulated power supply 5V), however I am not understanding what's the point of the resistor R. Is it a load resistor? Cause i thought these needed to be before ...
2
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5
answers
5k
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Is it possible to use 7805 regulator without capacitors at its input and output pins?
I have to drive a magnetic buzzer whose current is 50mA and max. voltage is 6V. I will use 7805 regulator to drive it as my supply voltage is variable 9V to 24V DC. There will be another small load ...
- 1,479
2
votes
1
answer
889
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Current-limit circuit for 78XX voltage regulators
I need to find the value of Rsc and R1 in the following circuit:
In this circuit, Q1 is the high-current pass transistor. Its emitter-to-base resistor has been chosen to turn it on at a given load ...
1
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2
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Why peak output current is greater than short circuit output current in 7805 voltage regulator?
This is the datasheet of 7805 voltage regulator produced by "Continental Device India Limited".
Question:
Why is the peak output current greater than short circuit output current?
Shouldn't the ...
1
vote
3
answers
578
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H-bridge with 7815 regulator
Could anyone explain to me why my 7815 regulator gets hot and eventually blows up ??
- 154
1
vote
1
answer
361
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3 terminal regulator max input voltage with zener at adjust pin?
Quick question: If I stick a zener at the adjust pin of a 3 terminal linear voltage regulator, the allowable maximum input voltage will also increase by the breakdown voltage of the zener used... ...
- 2,177
5
votes
1
answer
650
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7805 sense resistors
In this answer, there is a schematic showing the internals of a 7805 voltage regulator, reproduced below:
First of all, what is the sense pin in the first place? Every 7805 I've ever seen had three ...
- 35.2k
4
votes
1
answer
1k
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Using two voltage regulators (780x) in series to prevent heat sink
(updated due to remark of ChrisStratton).
I am wondering if it is a good idea to use two regulators in series.
What I want: using 2 12V Nema17 motors (using 12V, 1.7A each).
Using a microcontroller ...
- 14k