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  1. AnalogKid

    Charging Batteries using a Power Supply

    There are different variations of internal construction that make different manufacturers products...different. Note that "frequently" and "recommended" are qualifiers covering hundreds of products from dozens of manufacturers, not absolutes. The data sheet lists the max. charge rate. To...
  2. AnalogKid

    Logic family selection

    No, you don't. You have to consider all *reasonable* failures. The circuit might fail because it was hit by an asteroid, but I would not spend design time trying to account for this. ak
  3. AnalogKid

    Logic family selection

    Pretty sure that doesn't matter, unless the control system is mounted to one end of the table... ak
  4. AnalogKid

    Logic family selection

    This is a strange requirement. How can this happen? Where is this pc board going to be located where its traces can be cut while in operation? ak
  5. AnalogKid

    Logic family selection

    Here is what I think so far. Section A is the two input signals. Section B is a bare minimum approach. Section C is a more traditional approach. These are designed to drive a CMOS logic gate input. Note that both B and C end with a pull up resistor as indicated in previous posts. Depending...
  6. AnalogKid

    Logic family selection

    Yes, the fact that you cannot rely on an open TTL input to float to a high condition. It floats high by accident, not by design. It is a relatively high input impedance condition, and radiated noise can cause the input to transition. For any logic family at any time, never leave an input...
  7. AnalogKid

    Logic family selection

    Going back to your schematic in post #11, that is a very strange way to produce a galvanically isolated pulse. Is it possible to substitute an optocoupler for the transformer? If so, the entire AND gate function can be performed with one resistor. ak
  8. AnalogKid

    Logic family selection

    The language translation is not going well, so lets discuss each gate individually. If the requirement is that each OR gate input go to a logic 1 if there is a trace cut, this can be done with a pull up resistor located very near to each OR gate input. Is this an acceptable solution for this...
  9. AnalogKid

    Logic family selection

    Any digital logic part with HCT in the number is *not* TTL. It is a CMOS part with TTL-equivalent transition levels but with the super-high input impedance of CMOS. Because the signal source has a wildly asymmetrical output impedance and cannot sink any current, this is not going to be the...
  10. AnalogKid

    Charging Batteries using a Power Supply

    SLA batteries frequently have a recommended charging current of C/10. For a 7 Ah battery, that would mean a charging current of 0.7 A. With two identical batteries in series the current would remain at 0.7 A. Of course, the datasheet for your particular batteries might spec a different...
  11. AnalogKid

    Logic family selection

    What are the power supply voltage and logic family of the OR gate? ak
  12. AnalogKid

    Logic family selection

    Yes, and it might be pretty simple if you give up some information. Make that ANY information. 5 posts and almost zero technical details.... What are the two driving signals you want to AND? What kind of circuit produces them? Are they digital signals,or analog signals that just happen to...
  13. AnalogKid

    Multi-Stage Amp Build

    What are the assigned output impedance and total gain? Since you will be getting the grade, not me, why don't you do some of the work? Based on your research and teachings, work up a preliminary schematic of each stage and post it so we have something to discuss. ak
  14. AnalogKid

    Multi-Stage Amp Build

    Homework problem?
  15. AnalogKid

    Logic family selection

    1. A resistor to GND will pull the input low if its normal drive signal goes to an open circuit. This will force an output state of 0. 2. If you are asking about a transistor failure *inside* the AND gate, there is no way to predict how that will affect the output, and no way to force the...
  16. AnalogKid

    Op Amp Chip, different type query.

    Probably a date code. 1408 would be the 8th week of 2014. A/B might be the production facility. ADI is an exceptionally friendly company to deal with. Contact them. ak
  17. AnalogKid

    Wire One switch to multiple batteries?

    So there is no physical or electrical connection of any kind from anything to anything else? ak
  18. AnalogKid

    Simple On/Off switch for multiple signal wires

    What kind of switch action do your want - alternate action (push on/push off), toggle, rocker, etc.? Many distributors and surplus stores have 3-pole and 4-pole toggle switches made by C&K, E-Switch, Also, etc. You probably will find double-throw switches more common. That's ok, just ignore...
  19. AnalogKid

    Wire One switch to multiple batteries?

    5 separate batteries - are the five circuits all separate, or interconnected somehow? If interconnected, please post a sketch of the overall wiring play. Without that there are too many combinations to discuss in text. If all of this is one big circuit, then you will need a 5-pole switch, of...
  20. AnalogKid

    2x tip31 and stereo female 3,5 mm jack

    The diode *across* the base and emitter can be just about anything - 1N4002-4007, 1N914/1N41478, etc. ak
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