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  1. CommanderLake

    Eye Movement Desensitization Rehabilitation device

    Its not really the dropout or max power output I'm concerned about its the heat and efficiency.
  2. CommanderLake

    Eye Movement Desensitization Rehabilitation device

    Turns out plccenter ship the NTE176 from the us and they have a minimum order of £35 any other ideas before I splash out?
  3. CommanderLake

    Eye Movement Desensitization Rehabilitation device

    Heh would u look at that... I just noticed the latest version of the circuit simulator has Schmitt's.
  4. CommanderLake

    Eye Movement Desensitization Rehabilitation device

    So BC327-40 for the outputs and www.plccenter.co.uk/Buy/NTE/NTE176 for the emitter follower yes? I'd like to know the Vbe at 0.1A too bad they dont have any graphs. You got the ): caught in the link btw.
  5. CommanderLake

    Eye Movement Desensitization Rehabilitation device

    I think I need to find a germanium BJT apparently they have a very low Vbe.
  6. CommanderLake

    Eye Movement Desensitization Rehabilitation device

    I probably should have mentioned this sooner, it will be powered by 3x AA batteries will i need any bypass caps?
  7. CommanderLake

    Eye Movement Desensitization Rehabilitation device

    Price is not a problem unless it costs something like £100. The OPA2350 has a wider output voltage and current range is there anything wrong with that?
  8. CommanderLake

    Eye Movement Desensitization Rehabilitation device

    Right so op-amp it is then if you can find an even more ideal one here I can get free samples: www.ti.com/lsds/ti/amplifiers-linear/precision-amplifier-products.page#p2954=CDIP;CDIP SB;PDIP;TO-220&p480=2&p1261min=1.4;1.8;2;2.2;2.3;2.5;2.7;3
  9. CommanderLake

    Eye Movement Desensitization Rehabilitation device

    You want me to use a Schmitt inverter yes I know I'm looking for 8 pin DIP alternatives.
  10. CommanderLake

    Eye Movement Desensitization Rehabilitation device

    I am aware how an op-amp works and I can do surface mount soldering but making a PCB is either expensive or tricky, how about this: http://uk.farnell.com/texas-instruments/cd40107be/dual-2-in-nand-40107-dip8-18v/dp/1121598
  11. CommanderLake

    Eye Movement Desensitization Rehabilitation device

    I was not intending to use the NPN I was just messing about, would not a simple inverter do the same thing as a Schmitt? I can simulate that fine but I didn't want anything bigger than an an 8 pin DIP and I can only find inverters in 14 pin DIP's. Farnell has a minimum £20 order so I cant keep...
  12. CommanderLake

    Eye Movement Desensitization Rehabilitation device

    I prefer the specs on the LM393-N it has a picture of the oscillator circuit you told me about in the datasheet now I know how to do it properly. Have a look at my circuit (dont forget European resistors in the options menu) If the emitter follower will generate some heat would not a TO-220...
  13. CommanderLake

    Eye Movement Desensitization Rehabilitation device

    Why is 2.5 ohm too low, those values allow for a smaller capacitor and resistor on the negative feedback side. I get my stuff from farnell its much more user friendly than digikey, is a comparator basicly an op-amp thats made to output rail to rail and nothing in between? I think the Vce(sat)...
  14. CommanderLake

    Eye Movement Desensitization Rehabilitation device

    Wow thanks for all that, I'm starting to like the op-amp idea quite a lot I found the perfect component values that allow for a small 1uF capacitor with practical resistor values and precise frequency control: LINK Am I right in saying this BJT has a very low Vce(sat) and therefore a low...
  15. CommanderLake

    Eye Movement Desensitization Rehabilitation device

    When I tried the 555 in the circuit simulator I got the impression that holding a 50% duty cycle at the right speed is not easy but if theres a good way of doing that it might be an option. I can make an oscillator with a single op-amp and a symmetrical supply but is it possible with a single...
  16. CommanderLake

    Eye Movement Desensitization Rehabilitation device

    I was looking to see if there were a simpler circuit possibly avoiding logic components. I know I can use 2 op-amp's to generate a square wave but since the pods have a common ground at the connector I would have to use a PNP BJT for one pod and an NPN for the other but then the pod on the NPN...
  17. CommanderLake

    Eye Movement Desensitization Rehabilitation device

    You need Java installed so the applet can start. I have experience with a picaxe I was just exploring other options but it looks like the picaxe will be the best choice.
  18. CommanderLake

    Eye Movement Desensitization Rehabilitation device

    I need to make an EMDR device for my mum because they cost £125 to buy, she is fully qualified. I have the vibrating pods that the patient holds in their hands they have a standard 3.5mm stereo jack and use 0.1 amp at 4.4v, they need to vibrate 1 at a time left right left right and so on at...
  19. CommanderLake

    Ribbon cable 120 ohm?

    That makes sense.
  20. CommanderLake

    Ribbon cable 120 ohm?

    If I measure it with a multimeter will I get 120 ohm or is it AC impedance at a high frequency?
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