LDM

[@hamzaarif7249]

Lots of support from Pakistan

[@wolpumba4099]

*Dissecting a Vintage Boeing 727 EGT Indicator (Ametek, 1981)* * *0:11** - Boeing 727 EGT Indicator:* The video showcases a teardown and analysis of a vintage Exhaust Gas Temperature (EGT) indicator from a Boeing 727, manufactured by Ametek in 1981. * *0:29** - Thermocouple Sensor:* The indicator utilizes a thermocouple as its temperature sensor. [From Comments] It's unusual for airplanes to not use standardized signal transmissions like 5-20mA current, considering the potential for noise interference in the fuselage. * *0:59** - Capacitor Replacement:* Evidence suggests a capacitor within the unit has been replaced with a modern equivalent. * *1:18** - Modular Design:* The indicator features a modular design with interconnected boards that can be easily disassembled without soldering. * *1:58** - Potentiometer Resistance:* The potentiometer used in the servo motor mechanism has a total resistance of 27k ohms. * *3:39** - Thermocouple and Cold Junction Compensation:* The board housing the thermocouple input includes a cold junction compensator with a thermistor for accurate temperature readings. * *4:14** - Precision Op-Amp:* A precision op-amp (likely LH0044) with low offset drift is used in the thermocouple input stage for accurate amplification. * *5:22** - Functional Test:* The indicator is successfully tested using a thermocouple simulator, demonstrating accurate temperature readings across its range (0-850°C). * *8:01** - Piecewise Amplifier Explanation:* The video includes a detailed explanation of the piecewise amplifier circuit used to achieve the non-linear scale of the indicator. * *14:24** - Three-Scale Dial:* The indicator's dial has three distinct scales: 0-500°C, 500-700°C (with higher sensitivity), and 700-850°C. * *15:24** - Piecewise Amplifier Implementation:* The video highlights the specific implementation of the piecewise amplifier, noting potential improvements with the addition of diodes for better gain control and stability. * *17:24** - Servo Control Amplifier:* The servo control amplifier uses an error signal and feedback potentiometer to accurately position the indicator needle. This detailed breakdown of the EGT indicator provides valuable insights into its design and functionality, showcasing the intricate engineering behind this vintage aviation instrument. I used gemini-1.5-pro-exp-0801 to summarize the transcript. Cost (if I didn't use the free tier): $0.06 Input tokens: 16143 Output tokens: 546

[@АбуБандит-й9и]

What is software for circuit diagram name?

[@lelabodemichel5162]

PADS Logic

[@MP-ul]

Michel , will you remake any of them with modern components?.

[@Josh.Davidson]

Nice but i dont think this was used in the 727.

[@ivekuukkeli2156]

Excellent presentation of quite well designed circuitry for that time. But I wonder, why standard signal tranmissions are not used in airplanes? Like 5...20 mA current. Noise is about 500 mV signals along the whole aircraft fuselage from backmotors to nose instruments is difficult to fight against.

[@erwe1054]

логарифмические усилители- преобразователи с диодами в обратной связи ?

[@robertmonroe9728]

No, here it would not work as log amp.