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Title: Circuit having audio output pulse rate related to measured resistance and output pulse modulation related to measured capacitance
Claims: I claim: 1. The audio frequency signalling system comprising in combination: a pair of probes comprising insulated conductors having exposed tips, the total area of said exposed tips less than or equal to the square of the distance between said tips; a loudspeaker; an audio frequency generator circuit having a frequency determining network including the circuit path provided between the exposed tips of said pair of probes; and, said audio frequency generator circuit coupled to said loudspeaker and providing audio pulses at an increasing rate in response to increase in conductivity of said circuit path between the exposed tips of said pair of probes. 2. The invention according to claim 1 wherein said increasing rate of audio pulses in response to increase in conductivity includes a range which is substantially linear with increase in conductivity up to a rate of at least about six pulses per second. 3. The invention according to claim 1 wherein said insulated conductors have a cylindrical cross section and said exposed tips are substantially the cone shaped ends of said conductors. 4. Apparatus for monitoring the characteristics of soil comprising in combination: a pair of probes comprising insulated conductors having exposed tips; a loudspeaker; an audio frequency generator circuit for providing pulse of audio information having a pulse frequency determining and audio pulse modulating network including the circuit path between said pair of probes, said audio frequency generator circuit coupled to said loudspeaker and providing pulsed audio at a frequency which is a function of the resistivity of the soil between said probes, said audio frequency generator circuit further providing audio pulse modulation of said audio pulses as a function of the capacitance of the soil between said probes. 5. Apparatus according to claim 4 wherein said audio pulse modulation of said audio pulses comprises audio frequency modulation which decreases in frequency with increase in capacitance. 6. Apparatus according to claim 4 wherein said audio pulse modulation of said audio pulses comprises pulse width modulation wherein the length of said audio pulses decreases with decrease in capacitance. 7. An audio signalling system for indicating the resistance and capacitance between a pair of terminals comprising in combination: a loudspeaker; an audio frequency generator circuit coupled to said loudspeaker for providing audio output pulses; said audio frequency generator circuit including a pulse rate and pulse modulation determining portion comprising the circuit path provided between said pair of terminals said pulse rate and pulse modulation determining portion of said audio frequency generator circuit providing audio pulses at an increasing rate in response to decrease in resistivity between said pair of terminals and further providing audio pulses of increasing length in response to increase in capacitance between said pair of terminals. 8. An audio signalling system according to the invention of claim 7 wherein said increase in pulse rate is substantially linear over the range of about 40 Kilohms to 1 Kilohm. 9. An audio signalling system for monitoring the characteristics of soil comprising in combination: a loudspeaker; an audio frequency generator circuit coupled to said loudspeaker for providing audio output information representative of the characteristics of the soil; said audio frequency generator circuit coupled to a pair of probes and responsive to the resistance and capacitance qualities of the soil between said probes for providing said audio output information representative of said resistance and capacitance qualities of the soil; and wherein said probes comprise cylindrical cross section rods; said probes having cone shaped exposed tips, said audio frequency generator circuit coupled to said cone shaped exposed tips. 10. An audio signalling system for monitoring the characteristics of soil comprising in combination: a loudspeaker; an audio frequency generator circuit coupled to said loudspeaker for providing audio output information representative of the characteristics of the soil; said audio frequency generator circuit coupled to a pair of probes and responsive to the resistance and capacitance qualities of the soil between said probes for providing said audio output information representative of said resistance and capacitance qualities of the soil, and wherein said probes have exposed tips having a total combined area less than or equal to the square of the distance between said tips. 11. An audio signalling system for monitoring the characteristics of soil comprising in combination: a loudspeaker; an audio frequency generator circuit coupled to said loudspeaker for providing audio output information representative of the characteristics of the soil; said audio frequency generator circuit coupled to a pair of probes and responsive to the resistance and capacitance qualities of the soil between said probes for providing said audio output information representative of said resistance and capacitance qualities of the soil, and wherein said audio information has an audio pitch representative of capacitance. 12. The invention according to claim 11 wherein said audio pitch has a frequency which increases in response to decrease in capacitance. 13. The method of measuring and indicating the conductivity and impurity of a liquid containing material comprising: inserting a pair of probes into said liquid containing material; measuring the resistance between said probes; measuring the capacitance between said probes; and providing audio information signals representative of said resistance and said capacitance thereby indicating the conductivity and impurity content of said liquid containing material. 14. The method according to claim 13 wherein said step of providing audio information signals comprises providing audio information signals having a pitch which increases in frequency in response to decrease in capacitance thereby indicating less fertilizer impurity in moist soil. 15. The method of indicating the moisture and fertilizer content of soil comprising the steps of inserting a pair of probes into the soil; measuring the resistance betweeen said probes; measuring the capacitance between said probes; simultaneously generating electrical signals representative of said measured resistance and capacitance value thereby providing signals representative of the moisture and fertilizer content of the soil. 16. The method of claim 15 wherein said step of simultaneously generating electrical signals representative of said measured resistance and capacitance comprises generating periodic audio pulses having a repetition rate which is a function of the measured resistance and a pitch which is a function of the measured capacitance. 17. An audio signal generator responsive to the resistance and capacitance between first and second terminals comprising in combination: first and second probes; a transistor having base, emitter and collector electrodes; a capacitor having a first capacitor terminal and a second capacitor terminal; a resistor having a first resistor terminal and a second resistor terminal; a battery having first and second battery terminals; a pulse transformer having a primary winding having first and second primary winding terminals, and a secondary winding having first and second secondary winding terminals; a loudspeaker having a first loudspeaker input terminal and a second loudspeaker input terminal; said first capacitor terminal coupled to said first secondary winding terminal, said first secondary winding terminal coupled to said first loudspeaker input terminal, said second loudspeaker input terminal and said second secondary winding terminal coupled to said first battery terminal; said second primary winding terminal and said second probe coupled to said second battery terminal; said collector electrode coupled to said first primary winding terminal said emitter electrode coupled to said first battery terminal and said base electrode coupled to said first probe; and said second capacitor terminal coupled to said base electrode, said first resistor terminal coupled to said base electrode, and said second resistor terminal coupled to said first battery terminal. 18. An audio signalling system comprising in combination: a pair of probes arranged for disposition in soil; a transistor having collector, emitter, and base electrodes; a transformer having primary and secondary windings, said collector and emitter electrodes and said primary winding connected in series circuit between said second probe and reference potential; a source of potential coupled between said primary winding and reference potential; a capacitor coupled between said base electrode and said secondary winding; a resistor coupled between said base electrode and reference potential, said base electrode coupled to said first probe; and audio signal utilization means coupled across said secondary winding, said audio signal utilization means responsive to higher frequency audio pulses representative of fertilization levels of soil. 19. The method of measuring and indicating the conductivity and impurity of a liquid comprising: inserting a pair of probes into said liquid; measuring the resistance between said probes; measuring the capacitance between said probes; and providing audio information signals representative of said resistance and said capacitance thereby indicating the conductivity and impurity content of said liquid. Other info: Inventors: deBough, Bjorn N. (Seattle, WA, US) Application Number: 460712 Filing Date: 1974-04-15 Publication_date: 1976-02-03 Assignee: Primary Class(es): 324/664 324/439, 324/605, 324/694 Other Classes: US Patent Ref:
Other Refs: Primary Examiner: Krawczewicz, Stanley T. Assistant Examiner: Attorney: |
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