1. LED Switch Back Circuit
By: Joey Limonciello

2. What is a switchback circuit?
-Made to disrupt power to one part of the circuit when the other turns on. Some components used in it are:
-MOSFET P Channel: FQP27P06
-Diode
-Capacitor: 25µF
-Resistor: 100kΩ 1/2W
-Load Resistor: 6Ω 50W

3. Application 1157 2 prong LED bulb for use in vehicles
Bulb uses 20 white 1210 SMD LEDs and 34 yellow SMD LEDs.
White LED is significantly brighter than the yellow.
Yellow LED array in bulb consumes A and white consumes A
Load resistor to trick vehicle hardware.

4. Problem Statement LED bulbs purchased do not operate as planned
Add onto the simple switchback circuit by adding a capacitor
Size components properly to keep the white light from turning back on while yellow is flashing.
Figure out which side of wiring to install load resistor.

5. Design Multisim simulation to get a general idea of component sizes.
Build actual circuit and adjust capacitor size until time delay is suitable.

6. Design

7. Design of MOSFET P

8. Actual circuit demonstration
Video on flash drive

9. Implementation
Install circuit onto vehicle to address any issues

10. Installation
- Rebuild circuit using wires instead of building it on the bread board.

11. Installation
-Remove headlight and determine which side of prong is running light and turn signal.

12. Installation -Remove wire covering to expose wires.
-Splice in switchback harness into existing wires

13. Demonstration
Video on flashdrive

14. Future Refinement Add heatsink for load resistor
Build nice sealed circuit board to hold capacitor, resistor and MOSFET.

15. Questions?
Thanks for watching my presentation.