The NTE160 is a germanium mesa PNP transistor in a TO72 metal caseĭesigned for use as a preamplifier mixer and oscillator up to 900MHz. Germanium PNP Transistor (sounds like a likely match) The NTE is another transistor, NPN low noise high gain PNP audio power amplifier, NTE289A is NPN version (circuit should tell you PNP or NPN) I am gussing it is a VFL2744 not VFO 2744? I plugged in 2744 and got something different. For PC817 the rise time (TPD HL) and fall time (TPD LH) is 18us.Anyone know what a vfo 2744 might cross reference to? it is in the pream section of a Solid state magnavox consoleįor a 2744 I get a NTE 290A would this be correct? The below waveform shows the time taken for the output to transit from one state to another. The output will not get high as soon as the input logic is made low and vice versa. The complete working can also be understood form the GIF file above.Īnother important parameter to consider while using an Optocoupler, is the rise time (t r) and fall time (t f). This way the logic input will be reflected at the logic output and still provides and isolation between the two. This will short the collector and emitter and hence the Logic Output voltage will become zero. There pull-up resistor 1K acts as a load resistor.īut when the Logic input is made high, this high voltage should be a minimum of 1.25V (Diode Forward voltage) the IR LED conducts and so the photo-transistor is also turned on. Hence the Logic output will remain high, this high voltage can be set anywhere up-to 30V (Collector-Emitter Voltage) here I have used +5V. Now, when the Logic input is low the IR LED will not conduct and hence the transistor will also be in off state. Note: The ground line of the IR LED (pin 2) and the ground line of the transistor (pin 4) will not be connected together. Then Pull high the collector pin of the transistor using a resistor (here I have used 1K) and connect the collector pin to the output of your desired logic circuit. Using the PC817 IC is pretty much straight forward, we just have to connect the anode pin of the IR LED (pin 1) to the logic input which has to be isolated and the cathode (pin 2) of the IR led to the ground. This comes in very handy when you are trying to isolate a noisy signal from your digital electronics, so if you are looking for an IC to provide optical isolation in your circuit design then this IC might be the right choice for you. The digital signal given to the IR LED will be reflected on the transistor but there will be no hard electrical connection between the two. This IC is used to provide electrical isolation between two circuits, one part of the circuit is connected to the IR LED and the other to Photo-transistor. The arrangement and pinouts of the IR LED and the photo-transistor is shown below. When the IR LED is powered the light from it falls on the transistor and it conducts. So this IC basically has an IR (infrared) LED and a photo-transistor inside it.
PC817 Photocoupler has a transistor which is controlled based on light (photon). MOC3021 (Zero Cross TRIAC), MOC3041 (Non-Zero Cross TRIAC), FOD3180 (High-Speed MOSFET), MCT2E, 4N25
PHOTO TRANSISTOR CROSS REFERENCE DOWNLOAD
Note: More details can be found in the PC817 datasheet which is available for download at the end of this page.
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