In an astable multivibrator if[latex]\ R_{2}[/latex] = 60 kΩ,[latex]\ R_{1}[/latex] = 40 kΩ,[latex]\ C_{1} = C_{2}[/latex] = 2.9 nF, find its frequency and duty cycle.

[latex]\ T_{2} = 0.69 R_{1}C_{1} = 0.69 × 40 × 10^{3} × 2.9 × 10^{−9}[/latex] = 80 μ s = 0.08 ms [latex]\ T_{1} = 0.69R_{2}C_{2} = 0.69 × 60 × 10^{3} × 2.9 × 10^{−9}[/latex] = 120 μ s = 0.12 ms [latex]\ T = T_{1} + T_{2}[/latex] = 0.08 + 0.12 = 0.2 ms [latex]\ f = \frac{1}{T}[/latex] = 5 kHz Duty cycle =[latex]\frac{T_{1}}{T}=\frac{0.12 ms}{0.2 ms}[/latex] = 0.6

Question 7.6: In an astable multivibrator if R2 = 60 kΩ, R1 = 40 kΩ, C1 = ......

Pulse and Digital Circuits [1040456]

In an astable multivibrator if $\ R_{2}$ = 60 kΩ, $\ R_{1}$ = 40 kΩ, $\ C_{1} = C_{2}$ = 2.9 nF, find its frequency and duty cycle.

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$\ T_{2} = 0.69 R_{1}C_{1} = 0.69 × 40 × 10^{3} × 2.9 × 10^{−9}$ = 80 μs = 0.08 ms

$\ T_{1} = 0.69R_{2}C_{2} = 0.69 × 60 × 10^{3} × 2.9 × 10^{−9}$ = 120 μs = 0.12 ms

$\ T = T_{1} + T_{2}$ = 0.08 + 0.12 = 0.2 ms $\ f = \frac{1}{T}$ = 5 kHz

Duty cycle = $\frac{T_{1}}{T}=\frac{0.12 ms}{0.2 ms}$ = 0.6

Design an astable multivibrator, assuming that silicon devices with hFE(min) = 40 are used. Also assume that VCC = 10 V, IC(sat) = 5 mA. Let the desired frequency of oscillations be 5 kHz. For transistor used, VCE(sat) = 0.2 V, VBE(sat) = Vσ = 0.7 V. ...

Verified Answer:

\ R_{c} = \frac{ V_{CC} − V_{CE(sat)}}{I_{C...

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A symmetric astable multivibrator with vertical edges (see in Fig. 7.20) has the following parameters, VCC = 15 V, RC = 3 kΩ, R1 = R2 = R = 30 kΩ, R3 = 2 kΩ and silicon transistors with hFE = 50 are used. C1 = C2 = C = 0.01 μF. Verify whether the ON device is in saturation or not. Find its ...

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Assume

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Question: 7.7

A symmetrical collector-coupled astable multivibrator has the following parameters: VCC = 10 V, RC = 1 kΩ, R = 10 kΩ, and C = 0.01μF. Silicon transistors with hFE = 50 and rbb′ = 0.2 kΩ are used. Plot the waveforms and calculate the overshoot. Also plot the waveforms if the circuit uses p-n-p ...

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Question: 7.5

For the multivibrator shown in Fig. 7.13(a), VCC = 20 V, VBB = 10 V, R1 = R2 = R = 10 kΩ, C1 = C2 = C = 0.01μF. Find the time period and the frequency. ...

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\ T = 2RC ln \left(1 + \frac{V_{CC}}{V_{BB...

Question: 7.4

For the astable multivibrator shown in Fig. 7.1: (a) Find the value of C to provide symmetrical oscillations if R = 10 kΩ and f = 10 kHz. (b) Determine the values of capacitors to provide a train of pulses 0.1 ms wide and at a frequency of 1 kHz, if R1 =R2 = 1 kΩ (c) Find the minimum value of RC ...

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(a) Given R = 10 kΩ and

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Question: 7.3

For the astable multivibrator shown in Fig. 7.1: (a) Determine the time period and the frequency of oscillations if R1 = R2 = R = 10 kΩ , C1 = C2 = 0.01 μF. (b) Determine the time period and the frequency of oscillations if R1 = 1 kΩ, R2 = 10 kΩ, C1 = 0.01μF,C2 = 1μF. ...

Verified Answer:

(a) Given

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Question: 7.2

Consider the circuit in Fig. 7.16 (a) with VCC2 = 18 V, R1 = 250 kΩ, R3 = 200 kΩ, R2 = R4 = 1 MΩ, Re1 = Re2 = 3 kΩ, RC1 = 0.5 kΩ, RC2 = 0.2 kΩ, C = 0.1 μF and hFE = 30. Si devices are used. Calculate the voltages in the circuit and plot the waveforms to the scale. Also obtain the frequency of ...

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Given

\ V_{CC2}

= 18 V,

\ R_{3...

Question 7.6: In an astable multivibrator if R2 = 60 kΩ, R1 = 40 kΩ, C1 = ......

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