Question

what is the resistance of R,R1 & R2 to demonstrate this circuit to flash 1 time each second

(10 points) Design and build the following oscillator so that it flashes the LED once per second. The circuit should be built on a breadboard and the op-amp powered u Volt batteries (for supply voltage V, = ±9 Volt). a. sing two 9 R. flashes the Five additional points will be given if your oscillator, when you demonstrate, LED exactly thirty times in 30 seconds.

Answer 1

"The above given circuit is a Astable Multivibrator The formula for frequency of oscillations in an Astable multivibrator is f = 1/T = 0.5/RC ln[1 + beta/1 - beta] rightarrow eq (1) where beta = R_1/R_1 + R_1 = 1/2 The time period for our design is 1 sec substitute in equation(1) I = 0.5/RC ln[1 + 1/2/1 - 1/2] RC(ln 3) = 0.5 RC = 0.5/ln 3 RC = 0.455 \r\n For an op-Amp ""R"" value should be high & also We get RC = 0.455 which means if ""R"" value decreases, ""C"" value must be increased which increase size of circuit So let us consider R = 50 k ohm 50 k ohm times C = 0.455 C = 9.1 times 10^-6 So C value is approximately 10 mu F R_1 resistor is only for voltage division. So its value can be 10 k ohm R_1 = 10 k ohm For R_2, we need to include even diode forward voltage "

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