In the circuit below, v_s = -2 Volts, R₁ = 4Ω, R₂ = 3Ω. Find i in Amps. Give your answer to 3 decimal places.

For the loop picture below, v₁ = -2 V, v₂ = -2 V and v₃ = -0 V. Find v_x in Volts.

In the circuit below, i = 6.4 Amps, R₁ = 1.2Ω and R₂ = 4.5Ω. Find V_s in Volts to 2dp.

At the node picture below, i₁ = -1 A, i₂ = 0 A and i₃ = -3 A. Find i_x in Amps.

What is the power absorbed in Watts by a resistor with resistance of 5Ω connected to a current source of 2.6 Amps? Give your answer to 3 dp.

If i = 1A, v = -5V, the circuit element below is supplying power. True or false?

Design task – Logic gates

Specification:

In this design task you need to create a circuit implementing two logic gates, using transistors, as per the diagram below.

You are required to implement the above system where the LED turns ON when the output of the logic circuit is true/1. 

Inputs of the circuit are considered true/1 as outlined below. 

• LDR input is true/1 when it receives light of intensity above a certain threshold (you can set this threshold).  Otherwise, it's considered false/0.
• Push button input is true/1 when it is pressed, otherwise false/0.
• Slide switch input is true/1 when moved to the right, otherwise false/0.

Permitted Components:

• 1 x Mechanical slide switch
• 1 x Pushbutton switch
• 1 x LED
• 1 x LDR
• Transistors as needed
• Resistors as needed

Tasks:

1.  Draw the circuit diagram (using draw.io) showing all the electrical components.
2.  Present your calculations (you will be asked to explain how you did the calculations).
3.  Build the working circuit on a breadboard and bring it to the assessment (with the circuit diagram and the calculations). 
4.  Display the output waveform (from the LED) on one channel of the DSO and the input waveform from the LDR on the second channel of the DSO. 

Calculate the required values for the capacitor C1, and resistor RA, RB for an RC circuit to produce a signal with the frequency 50Hz (+/- 2 Hz) and a positive duty cycle of 85% (+/- 2%). You should make sure you can build this using the capacitors and resistors (to the nearest 10R) in your kit. You will need to use the formulas from the NE555/556 datasheet to do this.

Show your working steps. You can attach a photo into the submission if need be.

What type of waveform does the 555 timer in an astable configuration produce?