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Reasonable price for signal generator?

Discussion in 'Electronic Design' started by engineer, Feb 22, 2006.

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  1. engineer

    engineer Guest

    Gents and Ladies,

    I'm an engineer interested in marketing a portable (battery
    powered) square wave generator.

    I'd like to ask you what you think you would comfortably pay for
    the device I have in mind, as follows;

    Pros;
    50 ohm output impedance nominal (lower at DC, higher at 1 MHz)
    Output adjustable from 0 to 5 volts dc p-p.
    Square wave (50% +/- 0.5% duty) from 1 Hz to 500 kHz, triangle
    500 kHz to 1 MHz\
    Output to 250 mA nominal current, 450 mA peak (dc A, not rms)
    Nominal Battery life 58 hours.
    Power LED.
    BNC output
    Screw terminal-option Banana (2) output too.
    6 ranges, 1.8 decades each (overlapping), <1 Hz to >1MHz
    'Heavy Duty' ABS plastic enclosure with battery compartment
    Coarse frequency control pot 1.8 decades range
    Fine frequency control pot +/- 3% range
    Can drive a speaker directly in the audio range
    Can drive a light bulb
    Can drive any inductor since output protected by diodes.
    Can drive a short circuit continuously
    TTL compatible signal 1 Hz to 1 MHz.
    Power on switch located in level control pot.
    Overall dimensions 7" x 4" x 2"
    Output buffered, internal voltage regulation.
    Frequency continuously adjustable with low drift and jitter
    600nS rise / fall times.
    Weighs about 5 ounces and fits in any tool box.
    Slightly stylish ergonomic black case, rectangular footprint.
    Handmade to last a very, very, very long time.
    No chinese or indonesian slaves were used in the manufacture.
    Made in America, by an American (that and two dollars could get
    me a coffee;)
    Enclosure will resist cracking when dropped on hard surface.
    4 Controls.

    Cons;
    Only a square wave output, which turns into a triangle wave at
    500 kHz due to slew limit.
    2mV nominal output offset (never goes to exactly zero)
    DC offset not adjustable (signal goes from 0 to 5 or between as
    set by level control)
    No modulation input.
    No DC power input option (just the 9 volt battery)
    Doesn't go below 1 Hz or above 1 MHz
    Nicely labelled, but not painted-on lettering.
    No anti-skid feet.
    0 buttons or toggle switches.

    This unit is designed for portable use, by technicians in the field, or
    by engineers relocating their project from the lab to living room.
    It may be the only portable unit of it's capacity to have a bnc / 50
    ohm output - or - thumb-screw terminals for attaching small components.


    Given that it is good quality, with good, but slightly non-conventional
    appearance, what would you expect to pay for one if you needed it?

    They take several hours apiece to make one, but a buyer wouldn't know
    that... all surface mount components, lead solder, cleaned double-sided
    boards, conformal coated .. etc.

    Thanks very much for considering my question regarding the asking price
    for this unit.

    - Geoff
     
  2. For a change it's nice to see some cons listed!.
    There is very little electronics in there, so maybe 98% of the build cost
    will be mechanical items, costed out in small quantity say about $11.
    There *should* be an assembly time labour cost of maybe 4$, giving total
    manufacture costs of $15 and a sell out price based on say a 1.5 mark up of
    say $22.
    But ... I wouldn't buy one at that price :( reason is you're going to have
    to offer far far more in the way of spec' than you are here.
    For example, rise and fall times could easily be 10nS 0-5Vpp 50ohms all the
    way to 10MHz using just (cheap) transistors and a 74HC logic gate.
    Another example, The battery life of 54Hours is unbelievable. You must
    assume that at least some part of the time a bulb or speaker just might be
    connected. The case volume you have does not allow for a battery offering a
    realistic life greater than an hour or so.
    Honestly, I'm not intentionally being negative, it's just that I've seen the
    disappointment in peoples faces resulting after much effort and time has
    been spent on these type of projects.
    Best learning curve though is personal experience :).
    A valid offer price can be reached simply by pricing up your parts and own
    labour cost. Add a suitable profit margin on and then offer the unit for
    sale. (this is a UK perspective, details may be different in US but the
    principle is similar)
    john
     
  3. Ian Stirling

    Ian Stirling Guest

    Err, no.
    7"*4"*2"
    5V, 50 ohm, say a watt.
    6 NiMH AA cells - 12Wh of energy should be plenty.
    Though you could easily fit 36AA cells in there - for vastly more.
     
  4. Guest

    FORGET all about making "standard" pieces of test gear, buy the way
    nobody carries a squarewave generator in their toolkit, find yourself a
    "niche" device.
     
  5. A few comments...

    Price isn't the issue, it has to be useful to someone, it has to have a
    target market.
    Who needs a portable square wave only generator?
    The "TTL probe" kind can be handy for circuit work, and there are a few
    of those around already.

    7" x 4" x 2" is *HUGE*. Not exactly portable. If I want something
    battery powered and portable I'd want MUCH smaller than that. For that
    size I would want a whole host of extra features. The features given
    could be done in a truly pocket size unit, and that might be better
    received.

    It needs a sine wave output.

    It needs a low battery LED.

    The rise/fall time is poor. I assume the TTL output is much better?

    Dave :)
     
  6. Chris Jones

    Chris Jones Guest

    I wouldn't really want one, I would (and did) buy an old Wavetek 142, for
    about $100 plus $100 shipping. You might look at the front panel controls
    on that one, I believe that they are particularly well thought out. Having
    an extra output which is not 50 Ohm but can drive high currents (as you
    suggested) would be a nice extra feature for playing with AC motors etc.

    Chris
     
  7. engineer

    engineer Guest

    Actually it's 3.5 inches by 1 inch by 5.5 inches in case size.. it's
    just that the banana jacks and knobs extend that to other dimension.

    I've got some photos, and will mail you something from the first
    version which is nearly identical except for improvements in labelling.
     
  8. engineer

    engineer Guest

    Actually it's 3.5 inches by 1 inch by 5.5 inches in case size.. it's
    just that the banana jacks and knobs extend that to other dimension.

    I've got some photos, and will mail you something from the first
    version which is nearly identical except for improvements in labelling.
     
  9. Cool.
    Post them on the web so we can all see.

    Dave :)
     
  10. engineer

    engineer Guest

    It does drive those currents, but the evaluation of impedance is
    certainly not exact, and is based on a nominal 40 ohm output impedance
    of the driver chip and 10 ohms in series with that (protects the
    amplifier from major overcurrent situations) .. the impedance goes up
    with frequency.. according to the spec sheet, but it does drive across
    the 1 to 3.5 volt range at a megahertz into a 50 ohm load... barely but
    indeed... at 1 MHz the slew limit squashes the range a bit.

    I'll put the new label scheme on a new one and post a picture or that
    within 12 hours or so.

    Thanks for your input .
    Geoff
     
  11. engineer

    engineer Guest

    It does drive those currents, but the evaluation of impedance is
    certainly not exact, and is based on a nominal 40 ohm output impedance
    of the driver chip and 10 ohms in series with that (protects the
    amplifier from major overcurrent situations) .. the impedance goes up
    with frequency.. according to the spec sheet, but it does drive across
    the 1 to 3.5 volt range at a megahertz into a 50 ohm load... barely but
    indeed... at 1 MHz the slew limit squashes the range a bit.

    I'll put the new label scheme on a new one and post a picture or that
    within 12 hours or so.

    Thanks for your input .
    Geoff
     
  12. engineer

    engineer Guest

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