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请教-保护电路设计问题
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请教-保护电路设计问题# EE - 电子工程
g*n
1
看中了哪一盘?
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f*h
2
nero 6英文版,xp pro中文版,烧cd的时候没有报错,但读的时候不认。烧的是一般的
照片文档之类的数据。请问大侠,这可能是什么地方的问题?谢谢!
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x*9
3
用现有的0V/0.5V DC输出 控制 110VAC, 1A的交流电路
要求当控制输出由0.5V变成0V时,切断交流电路起到保护的作用
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j*y
4
火箭,总分下

【在 g*****n 的大作中提到】
: 看中了哪一盘?
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c*l
5
弄个amplifier把这个0.5V变成5V,然后drive个开关?

【在 x******9 的大作中提到】
: 用现有的0V/0.5V DC输出 控制 110VAC, 1A的交流电路
: 要求当控制输出由0.5V变成0V时,切断交流电路起到保护的作用

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c*u
6
热火现在炮轰了

火箭,总分下

【在 j**y 的大作中提到】
: 火箭,总分下
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p*o
7
找个合适的继电器(relay)就可以,不过你的控制高电平比较小,也许要放大一下。

【在 x******9 的大作中提到】
: 用现有的0V/0.5V DC输出 控制 110VAC, 1A的交流电路
: 要求当控制输出由0.5V变成0V时,切断交流电路起到保护的作用

avatar
j*y
8
火箭的防守
我有信心

【在 c***u 的大作中提到】
: 热火现在炮轰了
:
: 火箭,总分下

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d*s
9
楼上的我是dallas
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g*n
10
Good luck

【在 j**y 的大作中提到】
: 火箭的防守
: 我有信心

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x*9
11
我也是这么考虑的,现在relay有了,需要至少5V驱动,
请问放大电压用什么器件比较合适呢?关键参数是什么?

【在 p***o 的大作中提到】
: 找个合适的继电器(relay)就可以,不过你的控制高电平比较小,也许要放大一下。
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m*i
12
貌似猪皮基金亏损

【在 j**y 的大作中提到】
: 火箭的防守
: 我有信心

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f*0
13
0.5v trigger is tough to do, as it wouldn't be enough to turn on a bjt.
a few posibilities:
a) you can use some depletion mosfet which conducts at all voltage types.
b) you can use a comparator, preferrably single rail type. like lm311.
c) form a 0.2 - 0.5v supply, and apply it to the base of a npn bjt. type
emitter of your bjt to your control signal, and your relay to the collector.
when the control signal is at 0.5v, the be junction doesn't get enough
signal to turn on the bjt so the relay sta
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c*u
14
今天碰到火箭吃药了,明天继续。

貌似猪皮基金亏损

【在 m*i 的大作中提到】
: 貌似猪皮基金亏损
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f*0
15
the problem with using a depletion type mosfet is that most of those devices
don't have a clear turn on threshold. they gradually turn on and this can
be a death knoll in a switching application like yours.
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j*y
16
555555555
两天财产缩水1半

【在 c***u 的大作中提到】
: 今天碰到火箭吃药了,明天继续。
:
: 貌似猪皮基金亏损

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f*0
17
another approach may be to use some low power 555. the 2 triggers go off at
1/3 and 2/3 of Vcc so if you can get some 555 that runs on 1v Vcc you would
have a solution.
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c*u
18
pat pat
运气运气。

555555555
两天财产缩水1半

【在 j**y 的大作中提到】
: 555555555
: 两天财产缩水1半

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f*0
19
another solution is to use germanium transistors. those suckers turn on at 0
.2v vs. 0.6v for a silicon transistor.
that is an almost perfect solution for you: germanium transistors don't turn
completely on. but you can use it to drivea mosfet / silicon tansistor.
the old 3ax31 from China probably go for cents now, and nte has a lot of
germanium transistors.
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b*l
20
撕了裤衩上

555555555
两天财产缩水1半

【在 j**y 的大作中提到】
: 555555555
: 两天财产缩水1半

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g*u
21
check for some logic gate chips, some should have amplifier built inside.
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b*e
22
老老实实用放大电路+relay吧
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f*0
23
the problem is the 0.5v threshold. very few amps will be trigger by that
kind of voltage.
to "amplify" it, you will have to solve the power supply issue for such a
voltage.
the best alternative I think is a germanium transistor; then a comparator (
but you will have to solve interference issue so the comparator doesn't flip
accidentally).
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h*e
24
pmos input can handel 0-1V easily with 3V or 5V supply.
Using a differential PMOS inputs amplifier with negative-side set to 0.25V,
0 input will leads to ~5v output and 0.5V input will leads to ~0V ouput.
Althought gain could be low, it is good enough to make logic transition.
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f*0
25
mosfet typically has Vgs threshold at 3.5v, p-channel or n-channel. using it
always requires setting up a voltage, which I am not sure is superior.
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