body { $ /* Set "my-sec-counter" to 0 */ counter-reset: fignums;$.fignum::before { $ /* Increment "my-sec-counter" by 1 */ counter-increment: fignums; content: "Figure " counter(fignums) ": "; font-weight: bold;$.fig { $border: solid; margin: auto;margin-top: 10px;margin-bottom: 10px;width: 50%;height: auto;overflow: scroll;float: left;$img.image-center { $ width: 100% !important; height: auto !important;$ Students should work in pairs or groups of 3 for this lab, each person should build & test a portion of the sub-circuits.  Note that the depicted circuits are one option; you can build whatever is needed to achieve the same function from the parts provided.  

Example circuits from the pdf:

{ ${/download/attachments/205261967/VCO.png?version=1&modificationDate=1557421723000&api=v2}$ An example voltage controlled oscillator (VCO) circuit. The 555 timer chip is specifically designed to produce oscillations, in this configuration the frequency is controlled by the variable resistors and the 2.4 nF capacitor. When the capacitor charges to 23VCC23VCC23VCC { $\frac{2}{3} V_{CC}$ , the output will switch from high (VCCVCCVCC { $V_{CC}$ ) to low (ground) and the discharge pin becomes grounded, discharging the capacitor. When the capacitor voltage drops below 13VCC13VCC13VCC { $\frac{1}{3}V_{CC}$ the output will switch to high (VCCVCCVCC { $V_{CC}$ ),the discharge pin becomes high impedance (∞∞∞ { $\infty$ resistance), and the capacitor will begin charging. In this instance, the signal is modulated by the input to the control pin. { ${/download/attachments/205261967/LED%20Driver.png?version=1&modificationDate=1557421723000&api=v2}$ An example LED driver circuit.

{ ${/download/attachments/205261967/Detector.png?version=1&modificationDate=1557421723000&api=v2}$ An example photodetector circuit. When photons hit the FDS100 photodetector the result will be a current through the 446k resistor in the op-amp's feedback loop, which will make VoutVoutVout { $V_{out}$ proportional to light intensity. { ${/download/attachments/205261967/Clipper.png?version=1&modificationDate=1557421723000&api=v2}$ An example clipper circuit. This circuit drastically increases the magnitude of the signal from the photodetector with an inverting amplifier (op-amp and resistors), filters off any DC component (low pass filter), and then converts the output to a square wave of ±15V±15V±15V { $\pm 15 V$ using the comparator. { ${/download/attachments/205261967/Demodulator.png?version=1&modificationDate=1557421723000&api=v2}$ An example demodulator circuit. The variable resistor, inductor, and capacitor form a notch filter, which will be used to detect deviations from the carrier signal frequency (i.e. it picks out only the audio signal) The op-amp circuit is an active rectifier, ensuring that the output is always positive with respect to ground. The final RC network is a low-pass filter, which will eliminate unwanted leftover high frequency components of the signal.

{ ${/download/attachments/205261967/Speaker.png?version=1&modificationDate=1557421723000&api=v2}$ An example speaker amplifier circuit. This consists of a low-pass filter, a variable ac amplifier, yet another low-pass filter, and finally a follower connected to a speaker.