Alarm system having phase-sensitive bridge circuit

Details Alarm system having phase-sensitive bridge circuit Alarm system having phase-sensitive bridge circuit

1978-12-11

1980-10-14

Caldwell, Sr., John W.

Communications: electrical

Condition responsive indicating system

Specific condition

340658, 340661, 422 96, G08B 1710

Patent

active

042284295

ABSTRACT:
An alarm system for detecting a dangerous condition such as the increase in content of or the presence of toxic or inflammable gas in the air and giving a warning signal. The alarm system comprises an AC power supply, a full-wave rectifier connected to the AC power supply and rectifying alternating current from the AC power source into direct current. An AC bridge circuit connected to the AC power supply and includes a sensor element at least in one branch. An AC operational amplifier is supplied with power from the full-wave rectifier and receives an input signal which is the output signal delivered from the bridge circuit through a DC blocking capacitor. A thyristor is connected in parallel with the AC power supply, with its control gate connected to the output of the operational amplifier, and its main electrodes in series with an alarm indicator actuable when the thyristor is triggered into the conduction state. Such triggering occurs when the output signal voltage from the operational amplifier reverses its phase by 180.degree., i.e., when the resistance of the sensor element varies when a dangerous condition exists.

REFERENCES:
patent: 3221320 (1965-11-01), Yoneda
patent: 3950740 (1976-04-01), Greene
patent: 3961900 (1976-06-01), Gintelia
patent: 3997837 (1976-12-01), Betz et al.
patent: 4084156 (1978-04-01), Wittlinger
patent: 4146887 (1979-03-01), Magnante

Affiliated with

Also associated with

Rating

Alarm system having phase-sensitive bridge circuit does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Alarm system having phase-sensitive bridge circuit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Alarm system having phase-sensitive bridge circuit will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2103421