LM3886 Gainclone 2x68 Watt Full Amplifier Project

Description:

In this application, we are building a gaincard like amplifier. This application type is named gainclone in audio world. To take a satisfactory audio response,  we are adding a Linkwitz equaliser to the feedback line and adding bass compensation also.

We are using LM3886 which is the revised version of its brother LM3875.Briefly features of LM3886 are.

Maximum Output Power: 68W RMS - 108W Peak
THD: %0.03 at 60W
SNR: 110dB at 60 W - 92.5dB at 1W
PSRR: 120dB
Protection Circuitries: DC/AC Short circuit protection and thermal protection
Output Class: Conjugate AB-A

LDR & LED Pair Smoke Detector and Alarm by LM1801

Description: 

Smoke detectors are generally used in advanced alarm systems. Most of this professional devices use gas-detectors, ionization rooms or radioactive elements as sensors. In this circuit we are not using any of this complicated components. Instead of these, we are using two LDRs and one LED.

LM1801 special-purpose IC ,which is designed especially for smoke detectors, provides us building this circuit by using the minimum number of components. It includes one internal zener supply, two reference voltage outputs, one voltage comparator, fixing diodes and one 500mA output transistor.

Circuit is connected to the mains directly. D1 rectifies the alternating source and R7 reduces it to the level that the circuit can operate with.  C2 capacitor stabilizes the voltage and zener inside the IC regulates it

Two identical LDRs are connected in bridge type so this connection prevents the circuit from temperature changes and ageing effects...