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  1. R

    LC circuit Mutual Coupling

    Hi all, I have a LC tank circuit connected to a base of a NPN transistor via a 10K resistor. The emitter is tied to 0V. The collector has a 10K load resistor tied to 5V. The LC circuit has a resonance of 100KHz. I want to mutually couple this circuit so that the transistor is switched. How...
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    OptoMOS Relay

    I will send you the part numbers.
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    OptoMOS Relay

    Hi, I am looking at an alternative Opto MOSRelay, used for electronic switching - 12V supplies. Both are SOP4 packages, with the same pinout. The comparison has shown the following: 1. The new part has faster turn on / off times i.e. on - 1ms, off - 0.5ms compared with the older relay i.e. on...
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    Car Key Transponder

    I was only curious to see what was inside the key fob. Thanks
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    Car Key Transponder

    Hi, This is not the complete circuit, as there was a microcontroller on board. I was not sure how the authentication process is done i.e. how the code is transmitted to the key ignition and vice versa. Could it be some sort of ASK via the mutual coupling? Also I have not seen the LC circuit at...
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    Car Key Transponder

    Hi all, I have attached a circuit diagram from a car key transponder emulator that my friend has. I believe these work by putting the key emulator in an energised electromagnetic field, the inductor from the field mutually couples to the LC tank circuit (as in the diagram). I am not too familiar...
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    Crystal clock and USB operation

    Hi Thanks for your reply. Please could you explain why I would need a 240MHz crystal to achieve 480Mbits/s? I do not know and any help would be appreciated. Just a question, if I used a PIC 18F14K50, could I achieve the speeds of 480Mbits/s and 5Gbits/s with an external crystal. Please could...
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    Crystal clock and USB operation

    Hi all, I am using a PIC18F4520 microcontroller to use USB. I wanted to ask how the what crystal value I need to operate the USB at 480Mbits/s and 5Gbits/s. Is there a simple calculation that can help me? Thanks in advance
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    USB differential pair using Saturn PCB

    Thanks.
  10. R

    Power Electronics for Beginners

    Thanks.
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    USB differential pair using Saturn PCB

    Hi all, I am currently looking to use USB 2.0 (480Mbps speed) on a design. The USB differential signal coming in from a USB connector to a PIC microcontroller. I have tried using Saturn to give me a 90 Ohm differential impedance (see below), I am using FR4 PCB and 1oz copper (i.e. 18um copper +...
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    Power Electronics for Beginners

    Hi all, I am looking to re train in the field of electric vehicle technology. Alot of what I see is based on DCDC topolgies, inverters, SMPS design etc. Could anyine recommend a course (online) or a good book that can help me to understand this subject area? Thanks in advance
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    Tektronix 2336 scope no horizontal trace

    I wasnt sure if there were any high voltages lurking around on capacitors. Thats all.
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    Tektronix 2336 scope no horizontal trace

    Hi all, I havea Tektronix 2336 scope, this gas a fault, it does not show any traces. Is this easy to repair? Are there potentially any dangerous voltages present even after switching off the mains and opening it up. Thanks in advance.
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    Transimpedance v integrating amplifier

    Hi, I have attached a diagram of a photodiode connected to an opamp, this is an I to V converter or transimpedance amplifier, the current from the photodiode is converted into voltage by the feedback resistor. I have also seen the same can be achieved using a capacitor in the feedback instead...
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    Piezo buzzer operation

    Thanks for the reply. My other question is, how are the component values selected?
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    Piezo buzzer operation

    Hi, I have already seen this. However the circuit that I uploaded does not have a transistor in it. I think it needs a 'kick' to get it oscillating, then the feedback keeps it going. Not sure how you select the resistors and capacitor values. Thanks
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    Piezo buzzer operation

    Hi all, I have attached a diagram showing a 3 wire piezobuzzer connected to a micro. I am not sure how this works. I think you apply a voltage between the main and ground terminals. The feedback is then used to keep the buzzer oscillating around its resonant freq. I am not sure how the...
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    Electric Vehicle Technology

    Hi all, Can anyone recommend a good book that explains the technologies used in Electric Vehicles for beginners? Thanks in advance. PS: I have looked at various websites but need a book.
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    Power Electronics for Beginners

    Thank you very much for your help.
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