Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!hplabs!hp-pcd!hplsla!tomb
From: tomb@hplsla.HP.COM (Tom Bruhns)
Newsgroups: sci.electronics
Subject: Re: A whole lot of fun
Message-ID: <5170051@hplsla.HP.COM>
Date: 21 Jul 89 19:48:59 GMT
References: <23631@obiwan.mips.COM>
Organization: HP Lake Stevens, WA
Lines: 29

mark@mips.COM (Mark G. Johnson) writes:
>
>
>Here are the prices of components; minimize the total parts cost:
>   Resistors                      1 cent
>   Capacitors <= 0.5uF            3 cents
>   Capacitors > 0.5uF            15 cents
>   Diodes                         2 cents
>   Zener Diodes                   5 cents
>   Transistors rated < 0.5 Watt   8 cents
>   Transistors rated > 0.5 Watt  20 cents
>   Power MOSFET,     > 0.5 Watt  45 cents
>   Dual Opamp, 0.5 Watt          20 cents
>   Quad Opamp, 0.5 Watt          20 cents
>   Transducer (REQUIRED)        100 cents
>
>(My "solution" costs 152 cents; I suspect it can be done for about 141
> cents by a sufficiently clever design).

-  Are the two opamps really both $.20?
-  What does it mean to call the opamps "0.5 Watt"?
-  What accuracy is required, beyond the low "on" drop specified?
-  If your parts costs are right, and with reasonable accuracy,
   seems like $1.41 might be tough.  (You immediately toss out
   many of the parts as too expensive :-)

BTW, what about the PC board cost?  Connectors?  Mounting/enclosure?
If this were a _real_ problem, an obvious thing to work on is lowering
the cost of the transducer :-).