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  1. E

    threshold voltage of a MOS transistor

    Thank you for your response. In fact, the input of the switch is connected to a microcontroller (so I guess with low values of currents such as few mA). All I want is that when the microcontroller sends a pulsel of 0.5 or 1 V amplitude ( duration few miliseconds), the switch turns ON. And when...
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    threshold voltage of a MOS transistor

    Hello, I have a basic question: I would like to realize a switch (an interruptor) in a circuit, using a MOS transistor. I need to change the state of the switch, with a very low voltage (for ex. 1 V, or even 0.5 V). In other word: if I have input signal =0 --> switch OFF input...
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    Pulse delay circuit

    Hello, I am searching a circuit which can delay an input pulse to 0-30 ms. In other words, the input of the circuit is pulse of 80 V, with rising time=0. At the output of the circuit I would like to have the same pulse but with rising edge at time T (0-30 ms). I want to have a delay (T)...
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    How to have a single switch to open/close several lines at the same time

    No the relays should be closed when I press the button, then the signals can travel for 1-2 ms through the lines. I would say that the speed of the relays is not important for me. I only want to close them to let the signals pass through... Bests regards
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    How to have a single switch to open/close several lines at the same time

    Thank you very much. These contact lines carry a power of 14 W but only for few miliseconds (7V, 2A, 1-2 ms). The problem is that I would like to have a single button to control them (for easy using). So DPDT switches are good idea, but I should close them one by one to close the whole set...
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    How to have a single switch to open/close several lines at the same time

    Dear all, I would like to know if some one knows about a switch or a relay allowing to open/close several (precisely 18 contact line) at the same time? In fact, I want to have a single button to control all at the same time (if I press the button, 18 lines should become closed or opened). I can...
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    Maximum voltage generated by a function generator

    Hello, I have a very basic question (since I am not familiar with generators !). I would like to buy an arbitrary function generator (like Agilent 33210A). In the data sheet of this generator its written that the generated voltage is 10 Vpp for 50 ohm charge résistance. So, I want to know if I...
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    Techniques for testing PCBs in temperature chambers

    Dear all, I would like to know if someone has an experience with testing PCBs in temperature chambers following the production stage. In fact, we have to check 200-300 PCBs in 3 differents temperature : -40°C, 20°C and 60 °C. In our company, we have a temperature chamber allowing to acheive...
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    RC oscillator and Quartz frequencies

    Sorry but its not a microcontroller. Its a kind of circuit designed for Specific purposes (ASIC). That is why I need to put an RC circuit. and I put it because the quartz put some times to start. In this way I can measure times even before the quartz starts to run. But The only thing I know is...
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    Effect of parasit capacitor at the input of my digital circuit

    Thank you very much! In this case, I will not investigate this problem any more. Bests regards
  11. E

    RC oscillator and Quartz frequencies

    Thank you for your response. In fact in my data sheet, the only info I have is that the frequency of my RC oscillator should be in the window defined by the frequency of my quartz +/- 25%. When I do the calculation I am inside this window. No maybe sometimes I am not in this window, if the RC is...
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    RC oscillator and Quartz frequencies

    Dear all, I have a microcontroller for which I use a quartz crystal, and an RC oscillator circuit, both to produce an axact time measurement. My quartz has a frequncy of around 32 KHZ and my RC oscillator around 33 KHZ. I have a question regarding to the choice of my RC oscillator: - before I...
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    Effect of parasit capacitor at the input of my digital circuit

    No its not for a toch sensor. Its simply a circuit which permit to chosse an input between T1 and T7. These inputs correspond to different times (1s, 2s, etc...). If the user want to select the T1, he sould connect it to a ground. For each input I have a graound. So 7 ground. But, in général...
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    Effect of parasit capacitor at the input of my digital circuit

    Thank you very much for your response. In fact, I dont understand a lot of these kind of electronic!! Here is the image of my circuit: Inputs are T1, T2, ..., T7 I think if I remember that before we had pull-up transisitrs and every things was OK, then we put some invertors or something! then it...
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    Effect of parasit capacitor at the input of my digital circuit

    Dear all, I have a digital circuit (ASIC) designed for some specific purpuses. The circuit works well in most cases. However sometimes, it does not work i.e. I dont see any output. I am investigating if this problem could be related to parasit capacitor at the input of my circuit. The input of...
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    Capacitor discharges rapidly

    Dear all, I would like to know if you have some experience with SMD components pads. Especially I would like to know the difference between the Tin pads and SnPb pads? Which one is a better option in terms of the mechanical or thermal resistance? Bests regards
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    Capacitor discharges rapidly

    I can clearly see that at my ouput, the voltage is no more stable! I gives a pulse at my input, then I mesure the output with a high impedance voltmeter. The voltage drops rapidly to low values (0-1 V). Because of the complexity of my circuit, I can not isolate my capacitor from my resistances...
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    Capacitor discharges rapidly

    Thanks for your replies. Yes the diodes are all Zener. The first one I use to stabilize the voltage but the 2 others are chosen to have a minimum leakage current. For the connections pads its a very good suggestion. When I look to my circuit now I see that some parts of the pads are displaced...
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    Capacitor discharges rapidly

    Thank you for your reply. I use SMD type thick film resistors. (REF: RH73H2A15MKTN) Do you beleive that this could be the problem? Otherwise, could diodes also be the problem? Thanks and Bests regrds
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    Capacitor discharges rapidly

    Dear all, I have a very strange problem. I have the following circuit (picture attached): The circuit receives discrete pulses with 7.5 V amplitude and 2.5 A of current over 1-2 ms. The voltage is then stabilzed by a zener voltage at around 5.6 V. Then the capacitor of 150 uF will store the...
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