RF

=**Sustainability Analysis**=
 * Design Idea:** http://electronicdesign.com/ article/analog-and-mixed- signal/Crystal-Oscillator- Features-Low-Current-Low- Startup-Voltage.aspx

Clocks are essential for indicating, coordinating and keeping time. They are found in most advanced electronics in the form of oscillators. The purpose for their clock is to control the device according to time by using the clock as a trigger or timer. Without them, computers would have difficulty synchronizing multiple processes. The design idea listed above creates a new biasing schematic for a clock's system that features a lower start-up voltage and draws low current. By reducing the power consumed by a clock that always runs we can reduce the power consumed by the devices using the clocks. Sustainability is defined as a condition in which natural systems and social systems survive and thrive together indefinitely.[2] This design keeps with this idea to create a more sustainable system.

Ecology
"More then 3 million dry cell batteries are sold and discarded in the United States every year, producing more than 125,000 tons of waste." "With any battery disposal method, the potential exists to release heavy metals into the environment."[1] The heavy metals found in batteries can cause damage to the kidneys, liver, respiratory track, central nervous system and even the lungs.

Clocks are generally run by batteries and thus by reducing the energy consumed by the clock, we also reduce the number of batteries consumed each year. The original circuit was designed, in mind, for long battery life. To achieve this, the output transistor is chosen to give large gain at low operating current which is about 20uA. After the new biasing was integrated oscillating occurred at a supply current of less then 1uA and a supply voltage of less then .65V. This would drastically increase a batteries lifespan and consumes less power.

**Energy**
The original design for the 32kHz clock used at least 60uW constantly. With the new biasing design this value dropped down to at least .65uW supply. Not only does it save power by consuming less, it also saves the energy needed to break-down the batteries into reusable parts. All together this circuit is very energy efficient using large resisters to stop feedback current.

**Economy**
Designing new models that require less voltage and current from a source are usually great for saving money. Not only does the new design use less energy but also the ability to use smaller sources calls for a design that saves space. On the long run, having to change out batteries less often saves the cost of time and the batteries themselves. After batteries are used up the disposal of their toxic waste costs space for land fills and energy for breaking them down into usable parts.

The two low current PNP amplifiers are 2.9X1.3mm and cost roughly 49 cents and the 32.768-kHz watch crystal costs around 28 cents.[4] The most expensive part is the inverter, NAND, or NOR that buffers the output. The author recommends a CD4000 series IC to use as the buffer and its cost is around 3$. Other then these the resisters and capacitors account for very little of the price.

**Equity**
When looking at the equity impact there is no doubt that this design effects all users of technology. Clock are essential to everyday process's. Without time management regulating the day would be hardly manageable. By making sources smaller and the circuit less energy costly, clocks become more portable and easier to integrate with other technology. This improvement not only helps stakeholders that supply the parts but also provides better products for consumers that include several aspects. This is the same reason why hand watches are used less often. Instead of having a phone and a watch, we now have a phone that can give the time as well as many other functions. Unfortunately though, microprocessors are dissolving designs like this. One microprocessor can do the same job that this complete circuit can do however on a much smaller scale and with more functionality.

The green engineering design principles[6] offer additional design advice: > By conserving battery life less waste is produced and less hazardous materials are presented into the ecosystems. > Keeping a life-cycle of a battery in mind when designing. > Use cleaner battery sources and less power from sources such as power-plants. > Less power = less fossil fuels burned and less batteries used. > Batteries cause a large amount of waste. > Smaller sizes allow for production of smaller clocks which can apply to any culture or local geography. > Redesigning the biasing network for lower voltage/current necessities.
 * 1) Conserve and improve natural ecosystems while protecting human health and well-being.
 * 1) Use life-cycle thinking in all engineering activities.
 * 1) Ensure that all material and energy inputs and outputs are as inherently safe and benign as possible.
 * 1) Minimize depletion of natural resources.
 * 1) Strive to prevent waste.
 * 1) Develop and apply engineering solutions, while being cognizant of local geography, aspirations, and cultures.
 * 1) Create engineering solutions beyond current or dominant technologies; improve, innovate, and invent (technologies) to achieve sustainability.

References: [1] Universal Waste Coordinator. //Universal Waste - Used Batteries Environmental Factsheet//. North Little Rock: Universal Waste Coordinator. Web. 30 Apr. 2011. <[|www.adeq.state.ar.us/ftproot/pub/pa/brochures_online/05_Hazardous%20Waste/Universal%20Waste%20Fact%20Sheet%20-%20Used%20Batteries.pdf]>.

[2] Braun, David. "4E Sustainability Analysis." //HOME - Electrical Engineering Department - Cal Poly//. California Polytechnic State University. Web. 29 Apr. 2011. <[|http://courseware.ee.calpoly.edu/~dbraun/courses/4E-SustainabilityAnalysis.html]>.

[3] Braun, David. "EE413 Sustainability Analysis." //HOME - Electrical Engineering Department - Cal Poly//. California Polytechnic State University. Web. 29 Apr. 2011. <[|http://courseware.ee.calpoly.edu/~dbraun/courses/ee413/SustainabilityAnalysis.html]>.

[4] Unknown Author, 2N5087 ON Semiconductor Datasheet, "Amplifier Transisiter PNP silicon",Rev 4,3/2007,Semiconductor Component Industries, Available: [|www.onsemi.com/pub/Collateral/**2N5087**-D.PDF]

[5] Hagadorn, Hubert. "Crystal Oscillator Features Low Current, Low Startup Voltage." //Electronic Design Home Page//. Electronic Design, 23 Mar. 2011. Web. 01 May 2011. <[]>.

[6] Developed by more than 65 engineers and scientists at the Green Engineering: Defining the Principles Conference, held in Sandestin, Florida in May of 2003. The preliminary principles forged at this multidisciplinary conference are intended for engineers to use as guidance in the design or redesign of products and processes within the constraints dictated by business, government, and society such as cost, safety, performance and environmental impact. From U.S. EPA, //What is Green Engineering//, Sept. 13, 2007, Available: [|www.epa.gov/oppt/greenengineering/pubs/whats_ge.html]. [Accessed: Jan. 16, 2009]