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22 Threads found on Photo Coupler
Hi All 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 (...)
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
Thanks all 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 ---------------- chmr
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 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 (...)
check this one may be helpful
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
Hi all. 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
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 (...)
Optocouplers (Optically Coupled) and Fotocouplers (photocouplers) are same thing. Fotodarlington coupler have a Darlington Transistor in its output.Here are the images of a transistor output Optocoupler and a Darlington Transistor output Optocoupler. 61464 61465
how the hell should it work if the diode is in reversed bias while to the cathode vcc is supplied Did you notice that most standard optocouplers, either photo-diode or photo-transistor type, are using a reversed biased junction as photo detector? That's far from being specfic to 6N137 "digital" opto (...)
I have 3 of these I am wondering if they are bad. On one side reads same regardless of polarity 1k 1k 21k 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. Thoughts? will PC 817 versus EL 817 work the same?
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
The coupler looks like In the catalog photo, one port is terminated with 50 ohms, the other with a N connector.
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 ?
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 (...)
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
Opto-couplers / Opto-isolators ::
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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
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.
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
Hello All, 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 (...)