Welcome to Project 23 - Time Controlled AC Power Supply


sponsored by: caddock logo

1. Project Overview


The Time Controlled, Period and Cycle, AC Power Supply will be designed for Caddock Electronics Inc. for the purpose of providing electrical power for stress testing resistive components.

The Time Controlled AC Power Supply will contain a power supply (transformer) with a 120-volt, 60Hz, and up to 1000 Watt output. It will include three timers; 1) a process timer that will set the overall time duration for the process (between one second and sixty minutes), 2) a “cycle on timer” that sets the time for the power supply to cycle on within the overall time duration (the period may be set between one second and sixty seconds) and 3) a “cycle off timer”, to set the time off that immediately follows the completion of the “cycle on” time period (cycle off may be set between one second and sixty seconds). An override switch will be provided in order to choose whether or not to use the cycle timers during a process run.

When the Time Controlled AC Power Supply is cycled on and off, voltage spikes (transients) may be generated. During turn-on, in-rush current through the control electronics may be generated. Caddock Electronics would like such events to be minimized, and if possible, avoided. Included with the solution, Caddock would like the power supply to reach full on within one hundred milliseconds of the turn on signal and full off within one hundred milliseconds of the turn off signal.

An operator must be able to see and set the process and cycle times. The time remaining for the process and cycle timers must be displayed as well as the output the voltage of the Time Controlled AC Power Supply.

Final Presentation Video

Minimum Requirements


  • Output - 120 Volts and up to 1000 Watts will be provided to the output
  • Timers - Three timers will be used for the Time Controlled AC Power Supply. 1) A process timer that will set the overall time duration for the process. 2) A "cycle-on timer" that sets the time for the power supply to cycle on within the overall time duration. 3) A "cycle-off timer" that sets the time for the power supply to cycle off withing the overall time duration and immediately follow the "cycle-on timer".
  • Indicators - The operator of the Time Controlled AC Power Supply should be able to see if the process is running as well as which cycle is running. The operator should be able to hear when the process is complete.
  • Switches - The supply should be able to start and stop the process with two switches. The ability to turn off the cycling timers during the process will be provided. A breaker for the supply will allow the operator to turn the system off.
  • Displays - The Time Controlled AC Power Supply will display the voltage across the load. It will display time set and time remaining for the process timer. It will display the time set and time remaining for the cycle-on, and cycle-off timers.

  • Voltage Spikes and In-rush Current - When the Time Controlled AC Power Supply is cycled on and off, voltage spikes my be generated. During turn-on, in-rush through the control electronics may be generated. Such events will be minimized if not avoided.
  • Turn ON and Turn OFF delays - At turn on the power supply will reach 120 Volts within 100 milliseconds of turning on. At turn off the power supply will reach 0 volts within 100 milliseconds of turning off.
  • Case - The Variable Controlled AC Output Tester have an enclosure that provides easy access to the electronics for maintenance and improvements.

2 Background Research
3 System Requirements and Desired Features
4 Design Solutions
5 Top Level Block Design

5.1 Voltage Regulator
5.3 Current Controller
5.4 Timers
5.5 Transformer
5.6 Voltage Display
5.7 Micro-controller
5.8 Thermal
5.9 LED Indicators
5.10 Case
5.11 Auditory Alarm
5.12 High-Level Controller Code
5.13 Circuit Protection

6 Testing
7 Project Timeline
8 System Test Evidence
9 Expo Material

Group Members and emails


Joel Judd .................. juddjo(at)onid.orst.edu
Ryan Caddock .......... caddockr(at)onid.orst.edu
Jimmie Oates ........... oatesj(at)onid.orst.edu

Mentors, Sponors and Teaching Assistants





Contact with Sponsor and Mentor


  • Project Overview was discussed and approved by email with Caddock Electronics on 10/6/2010.
  • Requirements were attained during a meeting with Caddock Electronics on 10/15/2010.
  • Requirements and testing were revised and approved by Caddock Electronics and Dave Whited on 11/27/10


This project is licensed under the Other/Multiple/Unlicensed

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