Search results

Search Forums New Posts
  1. CDRIVE

    Arduino + Relay(220V) Problem.. Need Help!

    I would make your bridge filter capacitance 1000μF. Do you have a scope? Chris
  2. CDRIVE

    Arduino + Relay(220V) Problem.. Need Help!

    Absolutely. A relay's contacts are rated "Only" when its coil is receiving its rated voltage. When it's deprived of the rated voltage it's contacts ratings will no longer be valid. This isn't critical when the contacts current is very low but it's vital when dealing with current approaching...
  3. CDRIVE

    Arduino + Relay(220V) Problem.. Need Help!

    Uh, I should have examined your schematic more thoroughly before replying. That said I see some other issues. (1) 100uF is rather low for a PS filter cap. (2) You should consult with the 7805 Datasheet regarding best practices for selecting Cin & Cout values along with their physical...
  4. CDRIVE

    Arduino + Relay(220V) Problem.. Need Help!

    OK, this is going to begin with one of my rants about why posters fail to label their components; IE: R1, R2, Q1, U1, etc? I hate typing. So asking why Rx exists vs why is there a 1K resistor in the Emitter _ GND leg of the relay driver transistor makes things a hell of a lot easier and reduces...
  5. CDRIVE

    Controlling power levels of house electronics

    The hysteria about wallwarts left plugged in, TV's in sleep mode, electric clocks, etc was created by the over the top Greenies, who never took the time to consult with professionals. The same morons created the low volume (water conserving) toilet that takes at least two flushes the evacuate...
  6. CDRIVE

    LM3!* Again? Not really... but you could help...

    If you're implying that you made this transformer and it's (unpowered) output resistance = 27Ω then your transformer isn't going to deliver much current. In fact hanging a 27Ω resistor across the secondary winding is going to drop your output voltage by 50% and this does not take into account...
  7. CDRIVE

    How do I easily convert a stereo power output to mono?

    When we're talking about low power High Z outputs like earphones this is an easy thing to do. When you get down to 4Ω to 8Ω @ 50 Watts it's a new ballgame. You're going to have to sleuth that board to couple the two channels together at a point where power levels are considerably lower. BTW...
  8. CDRIVE

    DPDT Latching switches

    Here.... http://www.ebay.com/sch/i.html?_odkw=spdt+latching+push+button+switch&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.Xdpdt+latching+push+button+switch.TRS0&_nkw=dpdt+latching+push+button+switch&_sacat=0 Chris
  9. CDRIVE

    Problem: Schmitt Trigger not giving ON/OFF output

    After I posted, it hit me that a very common 555 can be used to make a very simple schmitt trigger. Do you have any? If not, can you get them? It will be fast and will give you more than acceptable TTL logic level output levels. IE, .. Lo ~= 0V Hi~= 5V. This will be especially true if it's the...
  10. CDRIVE

    Problem: Schmitt Trigger not giving ON/OFF output

    If Kris was still with us (RIP) he would have given you a complete schematic, parts list, list of suppliers and a whole lot of stuff I've probably missed. Above all and particularly because of your component procurement issues, it would have been completely DISCRETE! If you couldn't get the...
  11. CDRIVE

    Problem: Schmitt Trigger not giving ON/OFF output

    Bob, you read my mind. I was just about to post that the 741 is not considered to be the AA Fuel Dragster of the OpAmp world. :) Chris
  12. CDRIVE

    Why drop in voltage in this circuit ?

    Yup, I knew that you knew what I was referring to. I just wanted everyone else, especially Angy15 to understand. Thanks for posting it. Chris
  13. CDRIVE

    Why drop in voltage in this circuit ?

    Yes Bob except, that although Angy15's schematic doesn't indicate it, I'm assuming he's gating the base of Q1 with a switch or from a previous un-shown stage. So if it's a N/O switch it would be placed between the Vcc node of R1 and the Vcc respectively. If it's from a previous stage then R1...
  14. CDRIVE

    Why drop in voltage in this circuit ?

    Yes my post alluded to that. That's why I told him to move the divider to the base. The transistor's current gain will enable him to use the very common 1K resistors he's now using. It will also have the advantage of handling a greater range buzzer resistances without effecting the required...
  15. CDRIVE

    Frequency Mulitplier not working

    Impossible to evaluate your circuit without seeing it. I suggest that you post your schematic. Also: You do realize that all three inputs must be balanced circuitry? IE. not referenced to GND Common. Chris
  16. CDRIVE

    Trouble with a Tesla transformer

    Lots of weird stuff in your design. (1) Tesla coils typically imply coil input wave forms that are not sinusoidal. (2) F is only 105KHz but your transformer design is air core. o_O (3) Your secondary circuit ....:confused: Chris
  17. CDRIVE

    Why drop in voltage in this circuit ?

    This is happening because you're you've failed to include the resistance of the Buzzer in your voltage divider calculations. I suggest that you use the transistor itself to produce the 9V to drive the buzzer directly off T1's Cathode. You can do this by moving your voltage divider to the base...
  18. CDRIVE

    Need fundamental help understanding this circuit

    Yes, membership should make that mandatory with the flag icon displayed as nearly all of us have. It's a nice feature for those of us that don't have the entire world's national flags committed to memory. Chris
  19. CDRIVE

    78l33 circuit regulator, thought it would drop a 5v voltage to 3.3 v but no!

    Now that's good and simple thinking Steve. Decided to have a dry day? :p Chris
  20. CDRIVE

    78l33 circuit regulator, thought it would drop a 5v voltage to 3.3 v but no!

    You should be doing your experimenting using a regulated - current limiting supply. Not high Amp batteries that can melt things when you screw up. Also, you determine what a device draws by using an Ammeter. You should have one of those too. Use your DMM in Amps/mA mode. IMHO, I think the...
View older results
Top