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US 4,359,610 AGranted
Telephone ringing circuit
OwnerPan W. Changinventor
Life of this patent
Estimating the term…
Abstract
An improved telephone ringing circuit in which a ringing circuit is connected with a triac to allow an entry of ringing signals which are rectified by a full-wave rectifier connected in series with the triac. The D.C. voltage is being supplied to a sound producing device such as an oscillation circuit coupled with a speaker. The ringing circuit is also provided with a variable resistor for adjusting the D.C. voltage and a variable resistor in the oscillation circuit for adjusting the frequency of the A.C. output signals delivered by the oscillation circuit to the speaker.
Claims4
An improved ringing circuit for telephone sets, comprising:
- (a) a pair of input terminals having a first input terminal and a second input terminal for receiving A.C. ringing signals from the telephone set;
- (b) a full-wave rectifier having first and second input terminals, and first and second output terminals;
- (c) a capacitor connected in between the first input terminal for receiving A.C. ringing signals and the first input terminal of the full-wave rectifier;
- (d) a triac having an anode, a gate and a cathode, said cathode being connected to the second input terminal for receiving A.C. ringing signals;
- (e) a variable resistor having first and second ends, the first end being connected to the second input terminal of the full-wave rectifier and the second end being connected to the anode of said triac;
- (f) a neon lamp connected across the gate of said triac and the second input terminal of the full-wave rectifier, said neon lamp having a predetermined firing voltage lower than the voltage of the A.C. ringing signals;
- said neon lamp being arranged to trigger said triac for activating said rectifier to deliver a D.C. output;
- (g) a capacitor connected in parallel across the first and second output terminals of the full-wave rectifier;
- (h) a sound producing circuit for producing a sound in accordance with said D.C. output delivered by said full-wave rectifier.
6 more elements
Dependencies are inferred from the claim text.