Circuit book free

Why Class A ? Because , when biased to class A, the transistors are always turned on, always ready to respond instantaneously to an input signal. Class B and Class AB output stages require a microsecond or more to turn on. The Class A operation permits cleaner operation under the high-current slewing conditions that occur when transient audio signal are fed difficult loads. His amplifier is basically simple, as can be seen from the block diagram.

When the circuit at its close state, the IC will control the buzzer time using the resistor and capacitor. The buzzer sounds like alarm in the different frequencies.

•     Resistor R1 : 1.8k ohm
•     Resistor R2 : 1k ohm
•     Resistor R3 : 5.6k ohm
•     Resistor R4 : 480 ohm
•     Capacitor C1 : 2.2 nF
•     Polar Capacitor C2 : 0.022uF/6V
•     IC1 timer : NE555
•     Speaker SP1 : Tweeter 8 ohm
•     Power supply : 5V