Abstract: The present invention is directed to devices for detecting the moisture content of material such as a diaper using a change in bulk dielectric constant. More particularly, the invention relates to a moisture sensing device which provides an accurate indication of the moisture content of a material such as a diaper when merely placed in the vicinity of the diaper. In a preferred embodiment, the device is a hand-held device which can be readily transported and which can detect diaper moisture without piercing the diaper or attaching electrodes directly to the diaper.

Abstract: Apparatus and methodology for the transformation of living cells by the introduction of DNA thereto through transient pores created in the cell walls by the highly efficient electroporation of such cells in a liquid suspension with DNA. High efficiency electroporation is accomplished by the generation of a high voltage electrical pulse with precise characteristics determined necessary to optimize cell transformation and the application of such pulse to a sample of such suspension or by continuous flow of the suspension through a static electrical field under flow conditions to simulate the precise characteristics of such high voltage pulse. Thus, the suspension, whether treated as a non-flowing sample or as a continuous flow liquid suspension of cells in admixture with DNA, is subjected to a high intensity electric field at its maximum intensity in no more than about 100 microseconds and thereafter to reduced field intensity to zero field intensity in no more than about 5,000 microseconds.

Abstract: Microwave oscillator means wherein the resonant frequency determining element is a 1/2 or 1/4-wavelength folded dipole antenna that also serves as the transmitting and receiving antenna, capacitor means that is alternately charged and then discharged through said oscillator means until the voltage drops so low that oscillation ceases at which point the capacitor is charged again, negative peak follower means to convert the minimum voltage across the capacitor into a DC voltage, and comparator means to detect changes in the output voltage of the peak follower caused by the approach of a person or object to the 1/2 or 1/4-wavelength antenna.

Abstract: A method for detecting the change in the capacitance of an antenna caused by the approach of a person to the antenna, including the step of charging said antenna to a predetermined voltage relative to ground or a reference antenna, the step of discharging the antenna through a capacitor such that the voltage developed across the capacitor is proportional to the initial charge on the antenna, said charging and discharging steps being sequentially repeated, and the step of comparing the instantaneous voltage across the capacitor to the long term average voltage to detect transient changes caused by an increase in the antenna capacitance resulting from the approach of a person.

Abstract: An improved microwave proximity sensor including 1/4-wavelength folded dipole antenna performing the functions of a transmitting antenna, a receiving antenna, and a frequency determining element in a microwave oscillator.

Abstract: An apparatus for applying AC power to a load while maintaining a minimum charge across a capacitor for use as a DC power supply, that may be connected in series with the power supply and load, and does not require a parallel connection to the power supply, including power control means responsive to the phase of the power supply signal such that the voltage across said power control means is allowed to rise to a given voltage each cycle, before power is applied to the load, and charging means operable to charge said capacitor to said given voltage.

Abstract: Switching means for automatically determining which note in the entire musical spectrum is closest to an input frequency and display means for generating a visual display of the frequency difference between said input signal and the correct frequency of said note, specifically adapted for the tuning of musical instruments.