Did You Know...
...that while attempting to develop a super strong glue, 3M employee Spencer Silver accidentally developed a glue that was so weak it would barely hold two pieces of paper together? However, his colleague Art Fry needed the glue. Fry sang with his church choir and marked the pages of his hymnal with small scraps of paper that often fell out. He used Silver's glue to hold the papers in place. Today we call this invention Post-it Notes.
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| Number | Title | Issue Date |
| 7395308 | Grounded emitter logarithmic circuit A logarithmically-responding circuit includes a differential-input amplifier that drives the control terminal of a three-terminal device that exhibits an exponential response in its output current. This arrangement allows the third terminal to be grounded. In a pref... | 07/01/2008 |
| 7310656 | Grounded emitter logarithmic circuit A logarithmically-responding circuit includes a differential-input amplifier that drives the control terminal of a three-terminal device that exhibits an exponential response in its output current. This arrangement allows the third terminal to be grounded. In a pref... | 12/18/2007 |
| 7254490 | Marking system and method A methodology for facilitating the identification, authentication or quality control of packaged products is described comprising a marking and an authentication phase. In the marking phase the method involves obtaining an analytical specification, and for example a... | 08/07/2007 |
| 7194615 | Reconfigurable apparatus being configurable to operate in a logarithmic scale An integrated circuit has a command/control bus and a number of processing elements. The processing elements contain a number of parts, each part being connected to said command/control bus. Each one of the processing elements is re-configurable in response to comma... | 03/20/2007 |
| 6282290 | High speed modular exponentiator A modular exponentiator is adapted to receive a first communicated signal and derive a second signal therefrom by computation of a modular exponentiation of the form be mod n based on the first signal. The modular exponentiator divides the modu... | 08/28/2001 |
| 4939688 | Dynamic range converter providing a multiplicity of conversion ratios An electric signal converter utilizes a processing unit to establish a polynomial of n terms, each term being a power of the signal at the input terminal of the processor multiplied by an appropriate coefficient. Feedback of the input signal to the proces... | 07/03/1990 |
| 4901272 | Variable phase compensating apparatus A circuit arrangement is provided for phase compensation for a feedback amplifier circuit which has a variable gain depending upon the level of an input, so that a broadened frequency range in which the gain is substantially constant with respect to any g... | 02/13/1990 |
| 4791403 | Log encoder/decorder system A high speed form of finite precision binary arithmetic coding comprises encoding/decoding performed in the logarithm domain, resulting in facilitated computation based on additions and subtractions rather than multiplications and divisions. In encoding a... | 12/13/1988 |
| 4532604 | Predistortion circuit A predistortion error signal, corresponding to the third harmonic of an input signal, is generated by obtaining the absolute value of the input signal and multiplying it by the input signal of given sign to provide the square of the latter times the sign ... | 07/30/1985 |
| 4385364 | Electronic gain control circuit An electronic gain control circuit comprising a logarithmic circuit portion and an antilogarithmic circuit portion which is coupled to a current mirror circuit producing an output signal which is linearly related to an input signal applied to the logarith... | 05/24/1983 |
| 4356449 | Logarithmic attenuating circuit A logarithmic attenuating circuit is disclosed for multiplying by a constant factor the logarithmic range of input voltages which can be accomodated by a variety of test equipment. The circuit functions as an amplifier having a gain which varies inversely... | 10/26/1982 |
| 4300203 | Method and means for operating logarithmic circuits A method and means for operating log converter circuits in which the method comprises the steps of sequentially conducting to the input of the log converter circuit signals representing a known transmittance (T) of 100% T, 10% T, 1% T, and 0.1% T, these s... | 11/10/1981 |
| 4290111 | Decibel addition circuit An addition circuit for adding two decibel measurements received at input terminals 12 and 14, first substracts the inputs in a subtractor circuit 16 to obtain a difference d. Then, based upon the magnitude of the difference d, the addition circuit determ... | 09/15/1981 |
| 4245318 | Circuit breaker demonstrator and distribution circuit protection coordinator apparatus Demonstrator apparatus utilizes a display to portray in log-log coordinate scale the trip-time curve of a solid state (static) trip circuit breaker. A simulated static trip unit programmer is selectively adjustable to vary the shape and position of the di... | 01/13/1981 |
| 4206998 | Exposure control method for an automatic color printer with slope control The density of a negative is measured by a photocell and log converted through a log conversion amplifier. The log converted density is then converted with a properly selected gain to a value suitable for slope control. The converted value is exponential ... | 06/10/1980 |
| 4168492 | Temperature compensated antilogarithmic converter A temperature-compensated antilogarithmic converter has a temperature-sensitive signal generator for generating a temperature dependent signal which varies in proportion to absolute temperature; a multiplying means for mixing and converting the temperatur... | 09/18/1979 |
| 4156283 | Multiplier circuit A linear analog multiplier circuit for multiplying electrical quantities comprises a pair of differentially connected nonlinear control devices, for example, transistors, and at least one further semiconductor junction device exhibiting logarithmic charac... | 05/22/1979 |
| 4143363 | Nonuniform translation between analog and digital signals by a piece-wise linear process A weighted resistance network under control of combinational and sequential logic circuits provides a separate reference voltage at each of the digit times of the pulse code for comparison with an amplitude sample at the coder input. The difference voltag... | 03/06/1979 |
| 4139896 | Method and apparatus for producing nonlinear integral functions An integrator system is disclosed which incorporates a feedback control loop to vary the linearity of the integrator's response. In the preferred embodiment an electrochemical coulometer is used which stores the integral of a current that is passed throug... | 02/13/1979 |
| 4092724 | Polar converter A polar display representing the ratio of two input signals is provided by exponentiating the logarithmic ratio of two input signals. The DC voltage thus produced, which is proportional to the ratio between the two input signals is then multiplied by a co... | 05/30/1978 |
| 4090679 | Tape tension imparting apparatus A method of imparting a predetermined tension to a tape transported at a predetermined velocity from one to the other of the reels mounted on a pair of reel spindles at least one of which is rotated by a motor to have a rotational torque imparted thereto,... | 05/23/1978 |
| 4065682 | Logarithmic converter A system for deriving a voltage which is a logarithmic function of peak value of an audio signal, in which the audio input signal is amplified by means of an operational amplifier having bipolar feedbacks through a pair of oppositely poled rectifying junc... | 12/27/1977 |
| 4062013 | Non-linear type digital-to-analog converter A non-linear type digital-to-analog converter comprising a decoder, control switching circuits controlled respectively by the outputs of the decoder, and an exponential function generating circuit whose analog outputs are selectively produced by the opera... | 12/06/1977 |
| 4046999 | Logarithmic function generating system A logarithmic function generating system which generates an output signal bearing a logarithmic functional relation to the input signal. The time constant RC of a resistance-capacitance circuit is increased for every unit time elapsed in proportion to the... | 09/06/1977 |
| 4041299 | Multiplication apparatus A plurality of input signals to be multiplied are applied sequentially to a logarithmic time-width transformer in a form of electric analog signal in a predetermined order. The transformer converts each of the inputs into a signal having a time width in l... | 08/09/1977 |
| 4038566 | Multiplier circuit A gain control or multiplier circuit in which an ac signal is applied through bipolar diodes having logarithmic response characteristics to the bases of bipolar transistors connected in series and having an output at their junction, the diodes being direc... | 07/26/1977 |
| 4011502 | Logarithmic ratemeter with bistable signal comparison A logarithmic ratemeter has a plurality of bistable devices each having two inputs the first of which is connected to a common input line for receiving voltage pulses from a detector of atomic particles and the second of which is connected to a secondary ... | 03/08/1977 |
| 4004141 | Linear/logarithmic analog multiplier An analog device for generating an output signal which is proportional to the linear product between a first input signal and the antilogarithm of the second input signal, and comprising a means for applying the second input signal simultaneously and iden... | 01/18/1977 |
| 3967105 | Transistor power and root computing system A transistorized non-linear device is provided for converting input voltage signals to logarithmic current output signals and input current signals to exponential output voltage signals. This is performed using operational amplifiers having as the referen... | 06/29/1976 |
| 3965344 | Computer utilizing logarithmic function generators Analog apparatus for deriving any root of any input variable directly proportional to an input signal. A second signal directly proportional to the logarithm of the variable is divided in accordance with the root selected. The quotient is then compared by... | 06/22/1976 |
| 3940603 | Four quadrant multiplying divider using three log circuits Three log circuits are fed by respective x, y and z inputs, along with predetermined interconnections therebetween. The outputs from the log circuits are log z, log (x+z) and log (y+z). These outputs are fed to summing and anti-log circuits to derive the ... | 02/24/1976 |
