To demonstrate negative feedback a power amplifier is constructed from an operational amplifier together with a complementary pair of transistors as an output stage. The amplifier is developed and tested stage by stage, and at each stage the defects apparent at the previous stage are eliminated. (JN)

Discusses a method for viewing the square of a curve directly. Results are seen immediately and the curve can be manipulated to show, for example, the continuous effect of changing the zero level. The method is useful in studying the effect of squaring a curve or waveform in optics/electronics courses. (JN)

Discusses electric and magnetic forces between parallel-wire conductors and derives, in a simple fashion, order of magnitude estimates of the ratio of the likely electrostatic and electromagnetic forces for a simple parallel-wire balance. (Author/HM)

Thermal features of and beneath the surface of a sample can be detected and imaged with a thermal-wave microscope. Various methodologies for the excitation and detection of thermal waves are discussed, and several applications, primarily in microelectronics, are presented. (Author)

Students construct a Sierpinski gasket from resistors and measure its resistance as a function of size. Provides a brief review of what it means geometrically for the Sierpinski gasket to be fractal, followed by an explanation of how to analyze the electrical resistance on a gasket to find its fractal behavior. (MVL)

Describes laboratory experiments suitable for teaching the principles of digital electronics and computer interfacing to undergraduate chemistry students. Also describes the program for teaching laboratory uses of computers. The program functions to teach principles of computer interfacing while displacing as little chemistry as possible from the…

Describes several different philosophies of mind with each philosophy's explanation of the mind-body problem. Philosophies discussed include dualism, materialism, functionalism, radical behaviorism, logical behaviorism and central-state identity. (DS)

Describes an electronic technique for making a series of timing measurements in quick succession, using the signal from one photodiode. Two undergraduate experiments, one on linear momentum and the other on angular momentum conservation, are included. (HM)

Presents a laboratory experiment that was developed to acquaint physics students with field-effect transistor characteristics and circuits. Computer-drawn curves supplementing student laboratory exercises can be generated to provide more permanent, usable data than those taken from a curve tracer. (HM)

An advanced undergraduate laboratory experiment in inelastic electron tunneling spectroscopy is described. Tunnel junctions were fabricated, the tunneling spectra of several molecules absorbed on the surface of aluminum oxide measured, and mode assignments made for several of the prominent peaks in spectra using results obtained from optical…

Describes the use of transistors instead of valves for Lecher line and radiation demonstrations. Two oscillator circuits which provide power for Lecher line use are described. Impedance of Lecher line is also discussed. (HM)

The author draws attention to the possibilities of introducing the concept of electromagnetic energy flow associated with the Poynting vector at an elementary stage of physics instruction. (Author/SA)

Presents a method of studying RLC circuits with the help of the oscilloscope in the XYZ mode, complemented by an electronic device which generates a marker-trace on the screen and which is used to measure frequencies without the need of a reference point on the screen. (Author/GA)

Describes a low-cost instrument using a solar cell as a sensor to measure both instantaneous and integrated value of solar flux. Constructing and calibrating such an instrument constitutes an undergraduate experimental project, affording students an opportunity to examine a variety of aspects associated with solar energy measurements. (Author/SK)

Demonstrates that an electronic Josephson junction analog constructed from three integrated circuits plus an external reference oscillator can exhibit many of the circuit phenomena of a real Josephson junction. Includes computer and other applications of the analog. (Author/SK)