A.M. WEDNESDAY, 13 May minutes

Transcription

1 Candidate Name Centre Number Candidate Number 0 GCSE 293/02 ELECTRONICS MODULE TEST E1 HIGHER TIER AM WEDNESDAY, 13 May minutes For Examiner s use Total Mark ADDITIONAL MATERIALS In addition to this examination paper you may need a calculator INSTRUCTIONS TO CANDIDATES Write your name, centre number and candidate number in the spaces at the top of this page Answer all the questions in the spaces provided in this booklet INFORMATION FOR CANDIDATES The number of marks is given in brackets at the end of each question or part-question VP*(S )

2 2 INFORMATION SHEET This information may be of use in answering the questions 1 Resistor Colour Codes BLACK 0 BROWN 1 GREEN 5 BLUE 6 The fourth band colour gives the tolerance as follows: RED 2 VIOLET 7 GOLD ± 5% ORANGE 3 GREY 8 SILVER ± 10% YELLOW 4 WHITE 9 2 Preferred Values for Resistors E 12 SERIES OF PREFERRED VALUES 10; 12; 15; 18; 22; 27; 33; 39; 47; 56; 68; 82 and multiples thereafter 3 Resistance = voltage current ; R = V I 4 Effective resistance, R, of two resistors R 1 and R 2 in series is given by R = R 1 + R 2 5 Effective resistance, R, of two resistors R 1 and R 2 in parallel is given by R = R1R2 R1 + R 2 6 Voltage Divider + V S R 1 R 2 V OUT = R R 2 + R 1 2 V S 7 Power = voltage current; 2 2 V P = VI = I R = R 8 LED The forward voltage drop across an LED is 2V 9 Transistors (i) Current gain = Collector current Base current IC ; h FE = I B (ii) The forward voltage drop across the base emitter junction is 0 7V

3 3 Examiner Answer all questions in the spaces provided 1 Here is a list of electronic components: Diode Switch Thermistor Transistor LED (a) Which component has this symbol? Answer [1] (b) Which component has this symbol? Answer [1] (c) Which component from the list is an analogue input sensor? Answer [1] (d) Which component from the list could be used as a transducer driver? Answer [1] 2 A burglar alarm is needed for a shop An output should switch on and off continuously when the front door is opened An incomplete block diagram is shown below: Select 4 suitable sub-systems from the following list to complete the block diagram [5] Micro switch Buzzer Light sensing unit Temperature sensing unit Transducer driver OR gate AND gate Pulse generator Turn over

4 4 Examiner 3 The resistor colour code is given in the information sheet on page 2 Here is a diagram of a resistor The table shows the colours of the bands on a resistor Band 1 Band 2 Band 3 Band 4 Orange White Orange Silver (a) (i) Use the colour code to work out the value of the resistor Resistance in ohms = (ii) What is the percentage tolerance of the resistor? (iii) What is the tolerance in ohms of the resistor?

5 5 Examiner (b) Three other resistors are arranged as a voltage divider as follows: 12V R 1 = 10kΩ R 2 = 10kΩ R 3 = 10kΩ V OUT (i) Calculate the combined resistance of the parallel combination R 1 and R 2 [1] (ii) Calculate the output voltage V OUT Turn over

6 6 Examiner 4 The LED in the following circuit has a current of 15mA and forward voltage drop of 2V across it, when it is ON 15V 15mA 2V R (a) (i) What is the current through resistor R? (ii) What is the voltage across resistor R? (b) (i) Use your answers to part (a) to calculate the power used in resistor R (ii) Which one of the power ratings given below is the smallest that must be used for resistor R? 125 mw 250 mw 500 mw 1W [1]

7 7 Examiner (c) Use the formula in the information sheet on page 2 to calculate a suitable value for resistor R (d) Choose a suitable preferred value for resistor R from the E12 series in the information sheet on page 2 so that the LED has no more than 15mA flowing through it [1] Turn over

8 8 Examiner 5 The following incomplete diagram shows a circuit which should indicate when the light level is too low 12V Input X Input Y V OUT (a) The output V OUT of the comparator saturates at 12V and Complete the table for the given values of the input voltages Input X (V) Input Y (V) Output V OUT (V) (b) Complete the circuit diagram above to make: the voltage at input X high when the light level is too low the voltage at input Y adjustable [4] (c) Name one use for this circuit [1] (d) What does the comparator do in this circuit? [1]

9 9 BLANK PAGE Turn over

10 10 Examiner 6 The following circuit diagrams show part of a system used to switch on a 12V lamp The transistor is just saturated when V IN = 2 9V (a) The input voltage is 0 4V Write down the values of V 1 and V 2 in the boxes 12V V 2 = V R B V IN = 0 4V V 1 = V (b) The input voltage is increased to 2 9 V Write down the new values of V 1 and V 2 in the boxes 12V V 2 = V R B V IN = 2 9V V 1 = V

11 11 Examiner (c) The input voltage is 2 9 V and the transistor is just saturated, and has a current gain h FE of 120 The collector current through the 12V lamp is 60mA (i) Calculate the current through R B [1] (ii) Calculate the voltage drop across R B [1] (iii) Calculate the resistance of R B