L10109 1 Astable Multivibrator

for the next few weeks we're going to be working on a project that ties together all the things that we've covered up to this point in the semester this project is known as an oscillator or as an aable multivibrator it's going to involve transistors capacitors resistors um diodes pretty much everything we've talked about up to this point so let's go ahead and get started on this it'll be a three week project the first week we're going to talk about the theory and understand how this circuit Works we're going to simulate it and demonstrate how it works in simulation and then we'll breadboard it up into a prototype and show that with discreet devices uh that it do es exactly what we think it's going to do and we'll be able to look at it on the oscilloscope the second week we're going to we'll lay out the circuit to prepare for the um to prepare at uh for getting a printed circuit board made and then we'll get the circuit boards and on the third week we will go ahead and solder and then verify that the completed final project is uh working the way it's supposed to work this is the circuit we're going to be working with and let's just take a second to look at it and identify the the different parts of it first of all you'll notice that it's going to be a DC or at least the source is DC going to be using a 9volt battery there are one two three four resistors a couple of transistors and a couple of capacitors now notice by the way these L these diodes right here are LEDs and when this circuit is operating the LEDs flash one will be on and then the other one is on and then the other one and it just goes back and forth flashing those lights and it's all done automatically with this circuit so let's just look at uh first of all the the topography of the circuit you'll notice that these two transistors in fact let's even back up you'll notice that this circuit really consists of two circuits of the exact same type there's a an npn transistor a capacitor and these two resistors there's another res transistor a capacitor and these two resistors so really what we have is the same circuit duplicated or replicated twice and was we're going to see that this part of the circuit here works just like this part of the circuit does over here only that they work at different times you'll also notice that the left part of the circuit is connected from this point