22 Threads found on edaboard.com: Photo Coupler
I am using Two optocouplers to my inverter mains mode to invereter mode application.I used one opto coupler for zerocrossing detector and another for mains sensing voltage.i connected these optocouplers inputs in it working at all conditions?i am sending schematic as file.
if optocouplers inputs connected in (...)
Analog Circuit Design :: 08.04.2009 08:14 :: srinu9009 :: Replies: 5 :: Views: 1488
Hi sergio mariotti,
1. Unfortunately I have no access to such wideband directional bridges/couplers. I'd be grateful, if you can post or PM a sketch, a photo, or some draft drawing of such units.
2. The mentioned HP/Agilent models not just the upward extensions of the usual directional bridges (I have seen several up to 1 GHz), where the throug
RF, Microwave, Antennas and Optics :: 17.10.2004 10:57 :: g579 :: Replies: 4 :: Views: 3226
The circuit that I post was my boss give,but it can't work,the MOSFET is not seens there has some problems in the photo coupler circuit.
Can anyone tell me how to modify the circuit,but the only and most important is "cost".
Thanks a lot
Analog Circuit Design :: 13.01.2005 19:55 :: chmr :: Replies: 8 :: Views: 1566
These days I'm trying on a 40db coupler and the isolation is respected to be greater than 25db,while by using HFSS9.0 I got only 20db.How to improve the fact?
I used a stripline coupler,a very simple model.you can see from the photo.
Hope someone nice can help me ~~please.
Another,how to perform the mesh operation?I mean in a model some (...)
RF, Microwave, Antennas and Optics :: 29.09.2005 21:19 :: id_guy :: Replies: 2 :: Views: 676
check this one may be helpful
Analog Circuit Design :: 19.12.2006 11:49 :: artem :: Replies: 12 :: Views: 2830
The optocouplers BJT differs from a standard BJT that the area is much bigger to receive more infrared light and the base depth is much bigger to absorb a big part of the infrared. That has two consequences.
1. The internal Ccb is high.
2. The base transit time is high
If the collector current is not driven into low ohmic virtual ground th
Analog Circuit Design :: 30.03.2009 06:23 :: rfsystem :: Replies: 2 :: Views: 1058
I need some help with circuit in the attached file.
I need to momentary trigger a 240V relay through body capacitance.
Relay must be on just until I keep my finger on the touch plate.
I could design the circuit in file: from the upper part I get 12V and, with the Q9 transistor I can have 12V on C3 as long as I keep my finger on the touc
Analog Circuit Design :: 08.02.2010 21:38 :: marco0674 :: Replies: 3 :: Views: 778
For analog applications, there are two options to speed up an opto-coupler
- use it in current source mode, e.g. a cascode circuit or another means that creates a low (AC) load impedance, to overcome miller capacitance.
- use it as a photo diode. In this case, you'll need the base terminal.
Did you check, if the opto coupler pole is (...)
Power Electronics :: 03.09.2011 09:23 :: FvM :: Replies: 1 :: Views: 1231
Differences between opto-couplers, photo-couplers & photodarlington opto-couplers ?
Advantages & Disadvantages of these ?
Power Electronics :: 14.09.2011 07:32 :: dineshdeshmuk :: Replies: 3 :: Views: 1028
I'm trying to understand how this particular opto-coupler works internally.
Unfortunately i have not found any sufficient useful description on the way the internal section works.
I'll be glad if someone could elaborate on the way the photodiode works in the way it is connected according to the scheme
Analog Circuit Design :: 02.06.2012 06:09 :: TripACT :: Replies: 8 :: Views: 814
I have 3 of these I am wondering if they are bad.
On one side
reads same regardless of polarity
on other side of photo coupler
polarity reversed polarity
5.6m ohms 5.6 m ohms
5.6 m ohms 5.6 m ohms
9.7 m ohms open
These are in circuit tests.
will PC 817 versus EL 817 work the same?
Electronic Elementary Questions :: 05.11.2012 12:08 :: sdowney717 :: Replies: 0 :: Views: 212
You conclusion 1/2/3 should be o.k. The purpose on a opto coupler is to isolate two systems(GND and Vcc). The MCU output is driving the diode side and the photo transistor the isolated system side. For the other direction it is just opposite. The absolute maximum ratings in the data sheet is not the operating condition. These are the electrical ch
Electronic Elementary Questions :: 14.12.2012 03:01 :: HTA :: Replies: 8 :: Views: 495
The coupler looks like
In the catalog photo, one port is terminated with 50 ohms, the other with a N connector.
RF, Microwave, Antennas and Optics :: 02.07.2013 14:27 :: FvM :: Replies: 4 :: Views: 511
hi everyone ,
can i use an ir module (the one with 3 pins) instead of a phototransistor ,if yes, how can i do that , i mean what should i change ? whats the main diffrence between the 2 solution ?
Hobby Circuits and Small Projects Problems :: 05.06.2006 05:46 :: hassenman :: Replies: 5 :: Views: 865
opto coupler is used for the isolation between the input high voltage side and the low output side.
it controls the tiny swithching frequency.the output of the opto is connected to the EN pin of the TNY.the output current of the photo opto coupler,ie the current through the output diode of opto is controlled by the input voltage of the (...)
Analog Circuit Design :: 29.03.2007 04:57 :: cameo_2007 :: Replies: 4 :: Views: 2328
How can I measure the impedance of a small coil like the attached photo? Coil is 2mm coper wire located inside a quartz tube (4 mm diameter for water cooling). Coil diameter is 2.5 cm and lenght is 2.8 cm both like this and while plasma is ignited and coil is
RF, Microwave, Antennas and Optics :: 29.09.2009 02:27 :: steve_rb :: Replies: 5 :: Views: 1099
Opto-couplers / Opto-isolators ::
Microcontrollers :: 15.07.2011 07:59 :: nserudin musa :: Replies: 3 :: Views: 1328
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Business, Promotions, Advertising :: 14.10.2011 03:51 :: dhxiang517 :: Replies: 0 :: Views: 600
The dominant pole of an opto coupler is associated with the photo transistor, not the LED. (I'm not sure which side you mean with the unusual term "opto diode").
Usual TL431 circuits already achieve a current source characteristic a higher frequencies.
A cascode stage can partly improve the frequency characteristic of a resistor loaded poto t
Power Electronics :: 31.03.2013 14:29 :: FvM :: Replies: 12 :: Views: 735
If you are trying to get rid of common mode signal, you need to put similar impedances (resistance ) for both the inputs. This way, at the input of the photo diode you cancel out the common mode.
Analog Circuit Design :: 21.04.2013 22:59 :: shab_eda :: Replies: 4 :: Views: 205
You have to understand the mechanism of breakdown. Without knowing the schematic, it sounds like the diode is there to prevent reverse polarity exceeding the reverse breakdown voltage of the LED in the opto-coupler not the photo diode which is at it's output side. The resistor may be helping but the damage isn't caused by excessive c
Power Electronics :: 17.06.2013 11:51 :: betwixt :: Replies: 6 :: Views: 298
We are monitoring an AC voltage (200Vac) using a diode and resistor and photo LED of Opto-coupler in series. Here the Reverse break down voltage of diode is 700V, Resistor value is 200K ohm, Opto-coupler reverse break down voltage is 6V.
How to analyze impact of negative voltage (i.e. reverse break down voltage)? Where the (...)
Analog Circuit Design :: 30.07.2013 07:21 :: myatham :: Replies: 1 :: Views: 204