Search results

Search Forums New Posts
  1. Arouse1973

    15v power supply to 12v

    You need an LDO regulator or a SMPS. What current are you going to be drawing from the PSU? This will depend on what you choose, as all voltage regulator waste power and even more so as you increase the current you are taking from them. So you may need a more efficient regulator (SMPS) but if...
  2. Arouse1973

    How Transistors Work

    Yes I agree with Steve on this one. If you are using base current in your calculation then you are using a form of current control. But without knowing it you are changing the Vbe which is what is controlling the collector current. In this respect do we really care what the Vbe is doing as long...
  3. Arouse1973

    How Transistors Work

    Hope it makes sense to you? Adam
  4. Arouse1973

    How Transistors Work

    I think we can all agree that a BJT is a transconductance device. This is the collector current is a function of applied base emitter voltage. This means that a 57.6 mV change in base emitter voltage with produce an order of magnitude change in collector current. But how do we calculate all of...
  5. Arouse1973

    How Transistors Work

    He has copied a lot of this from another website I know very well so yes he would be accurate. But there is quite a lot to go through. I will look over this later for you and give my opinion. Adam
  6. Arouse1973

    Converting foreign appliances

    In the UK no change has been made, they know the varriance and have just fudged the figures. There is no plan to change anything it would be like re-building the great wall of china. Adam
  7. Arouse1973

    Converting foreign appliances

    As far as I know both UK and europe are classed as 230 Volts. Harmonisation caused UK 240 Volts to have a wider tolerance so it could match 230 Volts. The same in europe 220 Volts became 230 Volts. It was just a paperwork exercise and the voltages did not change so in the UK its still 240 and...
  8. Arouse1973

    Dancing Baby Groot

    Over in the UK in the 80's we had something called Dancing flowers. Here is a circuit I have just drawn for you which is what is used for the Dancing Flower. It might be of use to you also. It has a microphone, audio amp and motor drive transistor. Adam
  9. Arouse1973

    Voltage to current converter circuit

    Hello You don't seem to have looked at my circuit at all, this is what it does. It's a bi-directional current source. Perhaps you want to have a go at designing your own Op-amp. Here is just one I simulated, your going to need three so it might get a bit complex :) I understand you want to have...
  10. Arouse1973

    Help with small home project

    Yes correct, in this case the battery is most likely to have a higher voltage than the PSU. So a switch of some kind will be needed. Adam
  11. Arouse1973

    Help with small home project

    It will draw from which ever is higher voltage first but who cares. Does it matter?
  12. Arouse1973

    Mosfet switch design help

    http://www.digikey.com/catalog/en/partgroup/n-channel-logic-level-gate-fets/16119
  13. Arouse1973

    Mosfet switch design help

    Mr Tesla. I think designing your own mosfet might be behond this forum :) But you could look at logic level MOSFETS if you are planning on using a micro to switch it on. You dont show the value of capacitor or mention how quick you want it to be discharched in. This will make a difference. Adam
  14. Arouse1973

    what should consider when design motor speed controller

    Well what do you want the motor to do, you dont say. Forward ,backwards, brake? How do you want to control it? You dont say. Adam
  15. Arouse1973

    Re-wiring a powered Subwoofer

    I love these sort of diagrams. You spend half an hour tracing the lines only to find you have picked up on the border and have gone round in a circle lol. Anyone else done this.:) Adam
  16. Arouse1973

    Help with small home project

    I thought he was on about diode or-ing the battery and the PSU. So either could supply current, maybe I got that wrong. But thats how I would do it. May draw a circuit so it clear to all what you/he means. Cheers Adam
  17. Arouse1973

    Voltage to current converter circuit

    Final circuit of mine showing graph of output load from 1R - 5R. P1 set to 70%. Vin 2.5 V Sine. Thanks Adam
  18. Arouse1973

    Help with small home project

    Hi Gryd3 Sorry if I seem a bit confused I may have not understood you statement , but how is the diodes blocking capability dependant on the charge of the battery? Doesn't a diode block the majority of current (excluding drift current) when reversed biased? Obviously whilst under the breakdown...
  19. Arouse1973

    Voltage to current converter circuit

    For the graph you need to go to Analysis and then transient, choose you time base and ok. If you want to add further points to the graph you need to add a meter. Click the meter tab and choose the far left one called voltage pin. Add these to the schematic and then run analysis again. Cheers Adam
  20. Arouse1973

    Voltage to current converter circuit

    I used Tina, I had to pay for it but they do Tina Ti which is free but very limited. Series tuned circuit is when the capacitor is in series with the inductor. The LT1210 might be ok, why don't you try it in LT Spice? Adam
Top