Search results

Search Forums New Posts
  1. duke37

    Where to Purchase Transformers

    I assume this is for the mains frequency, 50 or 60Hz. You could wind a transformer yourself but it is not easy to get a neat result without a mechanical winder. One off specials can be obtained (in the UK) but are expensive. If you take a 24-0-24V 1A mains transformer and input 24V to one side...
  2. duke37

    driving analog frequency through a digital component

    Most digital circuits use edge triggering and need a sharp change of voltage on their input. If you use an analog signal, then nothing may happen or the circuit may go bananas. To avoid this the inputs of a slowly changing signal are passed to a schmitt trigger which rapidly changes from one...
  3. duke37

    i need help with a thyristor

    The TYN1012 seems be somewhat exotic, it is glass passivated and high voltage with a sensitive gate. The TO220 package is quite standard. The main characteristics to look for are:- Voltage 1000V Current 12A Gate current 15mA at 1.5V Edit Littlediode have the TYN1012 in stock.
  4. duke37

    Check my wiring scheme please

    You have DC voltage on pins 4 and 5 of the PID, but what value is it and what does the SSR need to switch it? You have voltage on pins 4 and 5 but have connected to pins 3 and 4. If the SSR needs a low DC trigger voltage you could perhaps test it with a battery. In #1 there are another set...
  5. duke37

    Check my wiring scheme please

    There needs to be more information on the PID controller. If pins 3 and 4 are just connected together when the output is ON then there is no power to the SSR. The mains does not have a + or - , it should be labelled L (line) and N (neutral). As I said, I have not used SSRs but I thought that...
  6. duke37

    Need help with Lcmeter project

    The terminal impedance of a dipole will vary geatly with frequency. An LC meter seems to be not the way to go. You can simulate a dipole with an antenna program such as MMANA or EZNEC. These will give theoretical termination impedance and you could find the actual value near the resonant...
  7. duke37

    mos operation regions

    Saturation is when the transistor is turned fully on like a switch. The current through it is controlled by the external circuit.
  8. duke37

    Oil temperature sensor, help?

    I do not know what the effects of over current will be. One effect will be to heat the sensor so giving the wrong resistance reading.
  9. duke37

    Small Circuit needed for New Product Design - Help!

    It seems that you will need to go the microprocessor route. This is not my area of expertise.
  10. duke37

    Oil temperature sensor, help?

    The point is that with a 5V supply and a resistance of 70 ohms, then the current will be 71mA. The maximum current is given as 1mA. Have I read the data wrong? One way would be to supply it with 1mA and measure the voltage across it, that would be well below 5V.
  11. duke37

    Small Circuit needed for New Product Design - Help!

    I doubt if you will be able to buy what you want, you will need to make it. You should decide what you want before you start to buy. We cannot tell you suppliers unless we know where you are. Didn't Tony come from East Cheam? You have been given two alternative solutions, one will need...
  12. duke37

    Oil temperature sensor, help?

    Taking the Bosch data, then B = 3534 and the resistance at 120degC is 70 ohms. Bosch data says 5V supply but 1mA maximum. I do not know how this can be done. You will need an op-amp to sense the thermistor output and provide say 1.2V at 120C which can be displayed on a simple voltmeter. It may...
  13. duke37

    Small Circuit needed for New Product Design - Help!

    Or you could go for 7 segment led displays. You would need a simple contact bounce suppressor on each switch. A cmos 4093 will count to ten and drive a seven segment display. led displays will take appreciable power.
  14. duke37

    Oil temperature sensor, help?

    Wikipedia gives an equation that thermistors fit. I have a 1989 Maplin catalogue which gives this equation ln(Rt1) = ln(Rt2) + B(T2-T1)/(T1/t2) where temperatures are in Kelvin B values are given for the thermistors they sell and are about 4000. You should measure the resistance at various...
  15. duke37

    help needed for engineering college project

    For mains frequencies, use 4% silicon iron. For high frequencies use ferrite. The number of primary turns will depend on the size of the core and the inductive current should be perhaps 10% of the load current. You will need to find a transformer design book.
  16. duke37

    Oil temperature sensor, help?

    I looked up 'boiling point elevation' on wikipedia and this says 0.17degC with 1% salt solution so you will not get more than 3 or 4 degrees. Acetic acid boils at 118degC but you would need to do this outside ! Thermistors can be described with a suitable equation. The constants can be...
  17. duke37

    Motion sensor to activate light and sound

    Detectors to turn on outside lights often use infra-red detection. They have a grid which gives a varying signal when the target image moves over it. The light level inhibition will need to be disabled. There are ultrasonic distance measuring modules which may work but it will depend on the...
  18. duke37

    Oil temperature sensor, help?

    The classic temperature reference near where you want is boiling water, 100degC The boiling point will rise with dissolved salt, you could try to find out the temperature rise with a concentrated solution. The resistance of a thermistor is very non linear so you will need to calibrate at 120degC.
  19. duke37

    Check my wiring scheme please

    I have not used an SSR so cannot comment on the light. Is this a led to indicate that it is enegised? If the output can drive a fluorescent light, then there is output but fluorescent lights need a constant voltage input. You can check the connection through the heater with an ohm meter...
  20. duke37

    Using Ardunio and MOSFET to drive 5V to 12V

    The link you give will not supply any information without logging in. Why not attach a picture? What is SOL, is this a solenoid? I cannot find details of the BUZ1015. I do not see how the circuit would work with a normal enhancement mode FET. It is easy to kill a mosfet if the gate is...
Top