5.1.1 State the function of resistor R1 - NSC Electrical Technology Electronics - Question 5 - 2021 - Paper 1
Question 5
5.1.1 State the function of resistor R1.
Resistor R1 is a pull-up resistor keeping pin 2 high and the circuit in its stable state.
5.1.2 Write down the voltage acr... show full transcript
Worked Solution & Example Answer:5.1.1 State the function of resistor R1 - NSC Electrical Technology Electronics - Question 5 - 2021 - Paper 1
Step 1
State the function of resistor R1.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Resistor R1 acts as a pull-up resistor which keeps pin 2 of the 555 timer high, thus maintaining the circuit in its stable state until the switch is pressed.
Step 2
Write down the voltage across Pin 2 when switch S is pressed.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The voltage across Pin 2 when switch S is pressed is 0 V.
Step 3
State whether the LED will be ON or OFF when switch S is pressed.
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
When switch S is pressed, the LED will be ON.
Step 4
Determine the typical threshold voltage of the circuit.
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The typical threshold voltage of the circuit is approximately rac{2}{3} Vcc.
Step 5
Explain why the switch bounce does not affect the output of the circuit.
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The switch bounce produces short on-off pulses that are shorter than the capacitor charging cycle. As a result, the output remains unaffected until the capacitor charges to the threshold level.
Step 6
Draw the output on the ANSWER SHEET for QUESTION 5.1.6.
97%
121 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Refer to the appropriate section on the answer sheet for the waveforms indicating the output response of the circuit.
