Switches and Relays

Task: Toggle Switch: similar to hallway light, each switch will turn LED on or off

(Schematic Goes Here)



Task: Create a circuit using pushbutton and relay. Push button will switch LED from lighting Red LED to lighting Green LED. Data sheet of the relay can be found here: http://www.hongfa.com/pro/pdf/HFD31_en.pdf

Task: A relay Oscillator. Now, the contacts in the relaxed state feed power to the coil as well as to one of the LEDs, but then it energizes the coils and opens the contacts making a very quick cycle. It oscillates 50 times/second. Only press it very briefly because it is likely to burn itself out or destroy.

Task: Adding capacitance. Add a capaciter to the circuit so that when the pushbutton is pushed, the LEDs alternate just like a car blinker light.

Schematics, Ohm's Law and Potentiometers

Introduction to Schematics and Data Sheets

Task: Find minimum resistance at data sheet Forward Voltage to produce brightest LED.

Calculation: [(Power supply) 5.15V - (LED Foward Voltage) 1.85V] /[(Current)/.02A] = 165 Ohm

Find next highest resistor, reduce cost and production time (real life). In my schematic, used 2 resistors in series to make 165 Ohm. Attach to Potentiometer to produce "Dimmer Light"

Solderless Breadboard, Effect of Resistance on LED

Summary: Created simple circuit with a Light Emitting Diode (LED) and various resistors

Above: Circuit with LED and 100 Ohm Resistor

Above: Circuit with LED and 1000 Ohm Resistor

Above: Circuit with LED and 10000 Ohm Resistor

 *In a LED, the positive lead is the slightly longer lead. LEDs will not work when backwards.
*Resistors can be read by their colors. Resistors can work backwards  Also, it does not matter the order in which the resistor is placed.
*The higher the resistor/resistance, the less bright the LED will emit.

Using a Multimeter, Testing Potentiometer (Pot) and Light Dependent Resistor (LDR)

Summary: We learned to conduct continuity measurements, resistance measurements, and voltage measurements using a Multimeter.

Above: Pot with minimum resistance

Above: Pot with maximum resistance

*Potentiometer maximum was 9.57 kOhm

*If opposite adjacent pins are connected, resistance is opposite of the range

*When pot is centered, resistance was half, therefore linear

Above: LDR with room light

5V Breadboard Power Supply

Task: Construct a 5V Breadboard Power Supply

Using a BlackBerry PSM04A-050RIM 5V 0.75A MiniUSB Charger, cut the MiniUSB side off. Splice the ends. Solder a butt joint to a 2 .1" prongs. Finish with heat shrink.

Test for polarity with a multi-meter. Connection was good and this will be used for future projects.