e-learning in Electronics

The Design Process Lesson 1: Circuit Simulations Crocodile clips Lesson 2: Design Decisions Modular circuit design Lesson 3: Realising my Design Crocodile clips + modular circuit design Lesson 4: Building the Prototype Breadboarding Lesson 5: Manufacture PCB design / Automatic manufacture

Circuit Simulations Crocodile clips Lesson 1 Circuit Simulations Crocodile clips

Objectives Aim Develop a students electronics design skills though e-learning. Develop confidence and knowledge in the use of crocodile clips. Objectives Construct simple circuits using crocodile clips. Make informed decisions over the choice of switches used in electronics circuits through practical experience of their operation. Incorporate logic gates as a means of controlling decisions within basic circuits. Discover ways of monitoring circuit action using probes, on screen messages and graphical images. Investigate the action of Astable and Monostable clocks using the prepared circuits in the package.

1. Navigation and Tutorial HTML link to crocodile clips

The Crocodile Tutorial The 2 tutorials under Help provides an effective route for investigating the initial workings of crocodile physics. Activity 1 Follow the Electronics tutorial. This will provide you with the initial skills required to investigate this package.

2. Switching In order to provide a clean transition from 0 to 1 in TTL logic circuits switches should be pulled cleanly between 0V and 5V. This is done using a pull down resistor R of 470Ω Activity 2 – Using JU1_switches Set the circuit with a logic monitor on the output, then investigate the action. Extension: The circuit you have made is commonly known as a Pull Up switch. Try designing a pull down switch. Sketch solution opposite:-

3. Logic Gates Activity 3: Investigate the operation of the AND gate using the components provided in JU1_And, then replace the AND gate with the OR gate provided. Now try completing the truth table for the OR gate below.

4. Output Displays – The LED array An LED normally needs a forward voltage drop of 2V and sufficient light is emitted with 10mA. A resistor is usually added to protect the LED from damage. Activity 4: Find the value of the resistor needed to control the current at 10mA when the supply voltage is 5V. (Use JU1_LED) Extension: Add an Ammeter in series with the LED, Resistor and find the safe current which turns on the LED. Fill in Answer here = Now retry this with a voltage of 9V as shown opposite. What protective resistor is needed in this case?

JU1_switches_NOT JU1_And_gates JU1_LEDs

5. Monostable v Astable Clocks This is a free running and produces a continuous supply of pulses at the output. Monostable. A trigger pulse produces a single pulse of fixed duration.

Creating my First Clock Activity 5: Using the models – Examples – Electronics Examples – Oscillator 1 provided investigate the settings required to produce an Astable clock with a frequency of 1Hz or period of 1s. You will need to alter the resistor that starts as 22k. Use the pulse in the graph to monitor the output frequency.