# Labs

lab # TOPICS lab exercises
1 Course Introduction How to connect the power supply

How to read a voltage, resistance, and current with the DMM

How protoboard is laid out

Each team builds a voltage divider with nom. 3.3 V output, and measure Vout. However, each team works in different resistance regimes (from 100's of Ohms to 100 kOhm)

Each team puts same set of load resistors on their dividers (100's ohms to MOhm)

All teams exchange data and plot results from all teams on one graph in their notebooks - discuss loading of dividers!
2 Resistors and Diodes LED lamp driver

Driving multiple LEDs in parallel and series

Use potentiometer to limit current and map I-V curve, each team with different color LED (one team with silicon signal diode)

All teams exchange data and plot results from all teams on one graph in their notebooks

Build and test 7805 circuit w/load
3 Bridge Circuits Build bridge rectifier with LEDs and use the load resister to limit current

See conduction paths light up depending on polarity of AC input

Measure voltage drop across load for both polarities

Measure voltage at each end of load w.r.t. ground of 9V battery for both polarities

Mechanical switch limits speed, so introduce function generator

Find maximum frequency that gives no flicker

Introduce Oscilloscope to view waveforms
4 Oscilloscopes and Capacitors Review operation of Oscilloscope

Add ripple reduction filter on bridge rectifier from last week
5 Filters Each team uses unique RC combination for low-pass filter, measures amplitude response at 10-12 frequency

All teams exchange data and plot results from all teams on one graph in their notebooks - discuss different turn-on voltages

Repeat 3) and 4) for high-pass filters
6 Relays and Transistors Drive motor off of power supply

Build relay driver to toggle LED

Build relay driver to toggle motor

Build NPN transistor switch driving LED and demonstrate

Drive transistor-controlled LED with function generator

Build and demonstrate NPN transistor switch driving motor
7 Op-Amps Build x2 gain inverting op-amp with potentiometer-based voltage divider as input. Drive a range of loads, compare results to bare divider

Give each team a different op-amp circuit to build, measure, and analyze

Each team presents results and analysis for its circuit to rest of class
8 555 Timer Circuit Build 555 as one-shot driving an LED

Present internal model and analyze

Build 555 as oscillator driving an LED
9 Sensors Measure resistance of CdS cells under low and high levels of light

Use results to select a fixed resistor, use that resistor and CdS cell to make voltage divider circuit to detect light

Use comparator to drive LED

Voltage divider (potentiometer) as input to comparator-driven LED

CdS cell divider as input

Light-activated motor

Add RC filter to get transient motor drive when light turns on (or off)