Search results

Search Forums New Posts
  1. CDRIVE

    Microwave Radio Project

    OMG! I didn't click that link till you posted this! Eeeek!:eek:
  2. CDRIVE

    Led transistor driver circuit help!!!

    Why does he need a 10K Gate to Gnd resistor? Wouldn't the existing 1K pullup resistors prevent the Gates from floating?
  3. CDRIVE

    Microwave Radio Project

    As Steve stated, output power is more of a safety issue than freq. The FCC limits experimental transmissions on none licensed transmitters to no greater than 1mW into a 50 Ohm test load. This is more of an insurance against interference to other services than it is about your safety though. Most...
  4. CDRIVE

    College Project

    I didn't want you to feel as though no one has read this. So, just to let you know.. I did.
  5. CDRIVE

    Birthday Project - Bacon-makin' alarm clock

    An automatic coffee maker is one thing but unattended cooking is entering a danger zone. Are you sure you've thought this through?
  6. CDRIVE

    university project help plzzz

    Tim, Yes and yes. Remote DTMF control has to be on the top wrung of fun, useful and powerful projects. You can turn your home PC on and off from anywhere in the world via the keypad of any phone. Start your car or disable it. The list is endless. Back in my dark days of dial-up I had two tel...
  7. CDRIVE

    Basic transistor Guitar Amp

    The OpAmp portion of this circuit will make a good guitar preamp by adjusting the bias so the output is 50% of the V+. The output of the OpAmp can drive a class B power amp stage that will drive speakers. https://www.electronicspoint.com/led-light-box-troubleshoot-t247751.html
  8. CDRIVE

    LCD Screen

    I don't think so. The RGB circuitry doesn't reside in the LCD.
  9. CDRIVE

    university project help plzzz

    Odd, I googled the term polyphonic ring tone an read a few descriptions including this excerpt.. "A polyphonic ring tone can consist of several notes at a time. The first polyphonic ring tones used sequenced recording methods such as MIDI. Such recordings specify what synthetic instrument...
  10. CDRIVE

    3V 2 LED flash circuit

    At 3Vcc your really pushing the limits because of the voltage drop of LEDs. This is the best I can give you but you must use common low power red LEDs. I've included pertinent notes on the schematic.
  11. CDRIVE

    Help on circuit

    This is how I interpreted it but I'll second the motion to replace what you purchased with the correct two lamp configuration. I post this for educational purposes only. Use at your own risk.
  12. CDRIVE

    university project help plzzz

    The cm8870pI is a DTMF (Dual Tone Modulated Frequency) decoder. It's not intended to decode music or voice frequencies. A DTMF Encoder is what your phone uses to dial numbers and a DTMF Decoder what the Tel co. uses to decode them. http://www.datasheetcatalog.org/datasheet/calmicro/CM8870.pdf...
  13. CDRIVE

    university project help plzzz

    Who's "they"? Is this a class assignment? EDIT: Duh, it's in your title.
  14. CDRIVE

    Simple voltage limiter question

    How did I miss this in my first reply? Anyway, what's your load that your voltage can swing from 0-19V but I=250mA, or is that 250mA @ 19V? A resistor and Zener, as I previously stated, isn't going to handle 250mA.
  15. CDRIVE

    Simple voltage limiter question

    If your load requirements aren't high a 5V Zener and resistor will do what you want. What's your signal source and what's the output Z? What's your load? Are you feeding this signal to a microcontroller, TTL logic block, other? Edit: Oops! Missed your 250mA requirements
  16. CDRIVE

    LED Light Box Troubleshoot

    Steve, if Desirae is driving a few Led strings then that's quite doable but if she wants a high current light show, that's a different ball game. I designed this circuit to keep Q1's rDS(ON) as low as possible. Creating feedback to pull the Gate voltage down will put Q1 in a region above rDS(ON)...
  17. CDRIVE

    LED Light Box Troubleshoot

    OK, I messed around with the TIP31 but abandoned it for a power FET. I did get a working model with the TIP31 but it's inferior to a power FET for this application. You can Google the OPA134 and the IRF510 data sheets for specs on these components. I chose the IRF510 only because it's common...
  18. CDRIVE

    LED Light Box Troubleshoot

    Desirae, are you still interested in building this from scratch using your TIP31?
  19. CDRIVE

    dual source input signal to single speaker

    Unfortunately what you're describing requires a tad more circuitry than a relay.
  20. CDRIVE

    Need help selecting an Emergency Stop

    Just a thought.. If the staff is going to keep hosing this equipment you may want to find a good Mil Spec or Marine switch. The ones with boots on them. ;)
Top