Search results

Search Forums New Posts
  1. dorke

    Calculating Resistance With Just Voltages? Basic DC Circuit Design

    Welcome to EP. You should supply each element it's specific working voltage. So only elements working at the same voltage can be paralleled. In your case the two 5v motors only, and they should be supplied with 5V . Is for school homework? It isn't a very practical thing to build with those...
  2. dorke

    Anyone know this manufacturer?

    That makes sense ,if it was a 2300v or 480V circuit indication light. Don't trow them away looks like they sell for some Dineros : 13$ used on Ebay This one wants 50$ for a new piece. You could sell them as well...
  3. dorke

    Diode Da Lima

    The need for the diode comes from the fact that you have a circuit that switches an inductive load on /off and vice versa in a "fast manner". In this case the inductive load is the relay/solenoid coil. The switching element is probably a transistor of the type BJT/MOSFET/Darlington etc. They...
  4. dorke

    A question about electrical Theory

    What is a "real life scenario"? Now-days we have virtual reality etc.;) Electric power is indeed P=v*i.( voltage*current) Changing power will happen if either v or i or both are changed. We can also say P=v*v/r=i*i*r. What is r(resistance)? r=v/i That may be split further into...
  5. dorke

    Anyone know this manufacturer?

    Looks like an antic. Where did this come out from? Could be monitoring high voltage?
  6. dorke

    3.3v Voltage Regulator

    An LDO like the LT1673 would be perfectly fine down to input voltage of 3.3V and current load of 350(400)mA to produce 3.0V . In the worst case scenario(400mA) there would be a slight violation of 25mV,It should work fine! notice, With dropping voltage to the ESP8266(In the area from 3.3v down...
  7. dorke

    3.3v Voltage Regulator

    Bob, the ESP8266 can work down to 3V, so a 3.3V LDO is fine for this app.
  8. dorke

    3.3v Voltage Regulator

    A solution for you would be the LT1763-3.3 or the adjustable version. At 400mA load it will have a max of 350mV dropout at T=25C. Here is the datasheet
  9. dorke

    Rf transmitter receiver

    Welcome to EP, When you say "I used syn115 and syn460r". What exactly do you mean? did you build a circuit around the ICs yourself? did you use a module with the ICs on it?
  10. dorke

    Amplifier for function generator output

    A few notes: 1.Driving motors with these kind of waveforms (sine, square, triangle, ramps) is mostly useless. Look up PWM etc. 2.There is a fundamental issue you have neglected ,the Bandwidth required from the AMP. It should be much higher than 10Khz for the case of the square signal...
  11. dorke

    Help identifying unknown component (SMD Diode?)

    Let me start by saying that SMD markings are a true pain in the a$$. LF is the marking logo of Little-Fuse ,part marking is 18A, it is a Uni-directional 18V/400W TVS diode P4SMA18A ,here is the datsheet It could be(less likely ) the 600W P6SMB18A. Here we have an example of ambiguity of...
  12. dorke

    Just murdered a MOSFET. What did I do wrong?

    There are a few issues with your design: 1. Secondary voltage of the transformer is too high to generate a 50VDC for the solenoid. it will create a DC voltage of around 65V(with peak that can be at around 74V!) . This will create a larger "ON" current which may damage both MOSFET and...
  13. dorke

    Just murdered a MOSFET. What did I do wrong?

    Well, A good starting point is to provide a detailed schematic including all devices part numbers . When using this kind of MOSFET to drive an inductive load like you do, a fast clamp diode on the load is crucial. Did you use one? which part? That MOSFET is not suitable to be operated from...
  14. dorke

    How do I test a Battery?

    W elcome to EP. 1. First thing is knowing the rated battery voltage and ,type. 2. Second the correct way to test a battery is in loaded condition,a multi-meter doesn't do that. it test in un-loaded condition.The proper load should be selected according to 1.
  15. dorke

    Sketch question

    You have to set the initial state of the buttons variable and relays to be not activated at boot , before and outside the above code like so: buttonState1 = high); buttonState2 = high); digitalWrite(relay1, buttonState1); // relay1 is set to off digitalWrite(relay2, buttonState2); // relay2...
  16. dorke

    Will this LED circuit work?

    Welcome to EP, It is very simple to do,your list is fine. You need : 1.A very small switch(much smaller than the one you picked). 2.A LED or more(how many? colors etc.?) 3.A battery,it can be as low as 3v button cell type (depends on number 2 above) 4. A resistor may or may not be needed. The...
  17. dorke

    Sketch question

    void loop() { // read the state of the pushbuttons value buttonState1 = digitalRead(button1); buttonState2 = digitalRead(button2); // check if at least one push-button is pressed if ((buttonState1 == LOW) || (buttonState2 == LOW) ) { digitalWrite(relay1, buttonState1); // if...
  18. dorke

    Identifying and replacing diodes??

    Welcome to EP, The correct way is to get the service manual of the "instrument" you are repairing. You should check the schematics, the PCB ,and the part list to find out the fullest info possible on the device. i.e. It's manufacture part number,it's function in the circuit, and the "free...
  19. dorke

    Help identifying this?

    Welcome to EP, We can guess ,but it would be simpler to connect it to a PC via the USB port...;) It should identify itself.
  20. dorke

    Please help identify this variable resistor

    You are welcome . Your terminology is fine,if you are getting a reading of "O.L" it stands for Over Limit. In this case it means over 20K (not necessarily infinity). The SCR is shorted Anode to Cathode ! Can you please check the Gate to Anode and Gate to Cathode in diode test mode flip the...
Top