Question

8 Assist with Theory please..

TOPIC: 4.3 MONOSTABLE OPERATION OF THE 555 TIMER DEVICE OBJECTIVE: Build and test the operation of the 555 timer IC which functions as a monostable multi vibrator. REFERENCE: Manufactures data sheets COMPONENTS: Ix IC 55.5 1 x 0.1 μ-capacitor Tnmpot Resistor pack EQUIPMENT: Development board Logic probe Multi metre INSTRUCTIONS: 1. Draw the circuit to use the 555 timer to function as a monostable multivibrator. 2. The output pulse must have a pulse length of 1 second 3. Calculate the necessary resistor values for your circwt Show all calculations in the practical book. 4. Build the above circuit connecting the output to your Red LED. (Remember current limiting) 5. Use a switch to trigger the 555 timer. (Make sure you know what level triggers the 555 timer IC) QUESTIONS: 1. Explain the difference from what you have experienced practically the difference between the 555 timer functioning as an astable and as a monostable multivibrator circuit. 2. Draw the pulse diagram that you observe from your circuif.

Answer 1

Morodtable av / Vec Trigge av Wok Wlok, Ry Vcc (5-15 Vald) Rexed look &R I T rimpot Bixchappe 6 1 7 appard GK Avec Joupput 147 Threshold I Trigger IC, = 0.1 MF 11 GND contendage I Reset - This pin rerede the internal flip flop, normally connected do Vec. working : - Initially, internal ff is at 0 is. Reset and transistor short circuido dhe a to ground & nothing happens further. LED2 also does nod glow as I it high. It begins with Si pushed Compan- -ador-t drives set pin of internal ff

Trigger Negative input of conparator / beds intorwal ff when voltage drops below avec Control Voltage - Controls the signing of 555 by overriding the 213 Vcc level of the vodtage divider retwork. by applying a voltage to this pin width of of con be varied in dependently of RC timing network. Threshold: - pereds ff when voltage exceeds 213 Vec.

to tigh as itt regative input is ilswer Chan veelz, now ☆ is Low, thich result in OLEDZ hlows a & Transistor switch off C: ftande do charge through R, contid positive inpud of comparatory is higher than (Vec+2)/3 in order to again aceset one ff. The rebadion bro time fR,G is- t = 1.1 hic R in ohms As aiveni t= 1 second C = O.1 MF 1x10 Farads c in farads then Ri= tici 7.1 C 111x10-7 R = gogogogohme 9.09x10 Al in software, we can take this value, But in reality are have to take 10 trimpot & adjuxt it.

ASUT 9V Ch.1 + - Ch.2 + - R4 0 1K U R3 4.1M Graph of XSC1 REKA 47 4 8 NO 1 5 IC1 NE555 Vol.98 C2 jº swl.1uF Key = 'A' 3 + 0.01°F D1 3