# Fire Alarm Circuit ## Description Fire Alarm circuit project, a thermistor works as the heat sensor. When temperature increases, its resistance decreases, and vice versa. Fire Alarm system works off a 6V-12V regulated power supply. Timer IC NE555 (IC1) is wired as an astable multivibrator oscillating in audio frequency band. ## Project Details - **Owner:** adrian95 - **Created:** 8/5/2021 - **Last Updated:** 8/8/2021 - **Visibility:** Public - **Stars:** 1 - **Forks:** 1 ## Key Components ### ? — [No Connect](https://www.flux.ai/vasyl/no-connect~ks.md) **Pins:** - P1 ### ? — [Thermistor](https://www.flux.ai/lwcassid/thermistor~ox.md) **Pins:** - undefined - undefined ### +6v — [Power Symbol](https://www.flux.ai/usairemalamgeer/power-symbol~qr.md) **Pins:** - P1 ### +6v — [Power Symbol](https://www.flux.ai/usairemalamgeer/power-symbol~qr.md) **Pins:** - P1 ### +6v — [Power Symbol](https://www.flux.ai/usairemalamgeer/power-symbol~qr.md) **Pins:** - P1 ### +6v — [Power Symbol](https://www.flux.ai/usairemalamgeer/power-symbol~qr.md) **Pins:** - P1 ### +6V — [Power Symbol](https://www.flux.ai/usairemalamgeer/power-symbol~qr.md) **Pins:** - P1 ### D1 1N4001 — [1N4001](https://www.flux.ai/ramprakashvishnoi8/1n4001-t~zyf.md) - DataSheet URL: https://www.mouser.com/datasheet/2/308/1N4001_D-1801424.pdf - Part Type: Rectifiers - Manufacturer Name: ON Semiconductor - Manufacturer Part Number: 1N4001 - Package: DO-41-2 **Pins:** - A - K ### DICHARGE — Label **Pins:** - P1 - P2 ### DICHARGE — Label **Pins:** - P1 - P2 ### EMIT — Label **Pins:** - P1 - P2 ### EMIT — Label **Pins:** - P1 - P2 ### IC1 NE555 — [NE555P](https://www.flux.ai/jharwinbarrozo/ne555p~rvz.md) - Part Type: Integrated Circuit - Package or Case Code: 8-DIP - Manufacturer Name: Texas Instruments - Datasheet URL: https://rocelec.widen.net/view/pdf/giqzbewdkx/slfs022i.pdf?t.download=true&u=5oefqw - Manufacturer Part Number: NE555P **Pins:** - CV - DIS - GND - Q - R - THR - TR - VCC ### LED INDICATOR — [LED](https://www.flux.ai/jharwinbarrozo/led-tht~gr.md) - Breakdown Voltage: 0V - Series Resistance: 0.42Ω - Emission Coefficient: 3.73 - Forward Voltage: 1.70 - Saturation Current: 93.2e-12A **Pins:** - ANODE - CATHODE ### LS1 8Ω 1W SPEAKER — [Loud Speaker](https://www.flux.ai/jharwinbarrozo/loud-speaker~aw.md) **Pins:** - undefined - undefined ### POINT 1 — Label **Pins:** - P1 - P2 ### POINT 1 — Label **Pins:** - P1 - P2 ### Q4 — [NPN Transistor](https://www.flux.ai/jharwinbarrozo/npn-transistor~hqd.md) - Leakage Current: 1e-13A - Beta / hFe: 100 **Pins:** - B - C - E ### T1 BC548 — [NPN Transistor](https://www.flux.ai/jharwinbarrozo/npn-transistor~hqd.md) - Beta / hFe: 100 - Leakage Current: 1e-13A **Pins:** - B - C - E ### T2 BC558 — [PNP Transistor](https://www.flux.ai/jharwinbarrozo/pnp-transistor~bl.md) - Beta / hFe: 100 - Leakage Current: 1e-13 **Pins:** - B - C - E *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/adrian95/fire-alarm-circuit~orl](https://www.flux.ai/adrian95/fire-alarm-circuit~orl).* --- *Generated from [https://www.flux.ai/adrian95/fire-alarm-circuit~orl](https://www.flux.ai/adrian95/fire-alarm-circuit~orl)*