This circuit uses a mixture of transistors, an IC and a relay and is used to automatically open and close a pair of curtains. Using switch S3 also allows manual control, allowing curtains to be left only partially open or closed. The circuit controls a motor that is attached to a simple pulley mechanism, to move the curtains.
Automatic Operation The circuit can be broken into three main parts; a bi-stable latch, a timer and a reversing circuit. Toggle switch S3 determines manual or automatic mode. The circuit as shown above is drawn in the automatic position and operation is as follows. The bi-stable is built around Q1 and Q2 and associated circuitry and controls relay A/2. S1 is used to open the curtains and S2 to close the curtains. At power on, a brief positive pulse is applied to the base of Q2 via C2. Q2 will be on, and activate relay A/2. READ MORE
To recognize the battery whether it is working or not is very difficult. Generally voltmeter is employed for checking purpose of state of battery. Now, here is very simple circuit utilized to check the state of battery. Circuit Description The entire circuit of universal battery tester is build around dual comparator IC TL072 (IC1) followed by other component. The two independent comparator is used here as operational amplifier. The inverting pin of these two operational amplifiers is fed through potential divider network made from resistor R1 and R3. Rest of the component is utilized to maintain threshold voltage. State of LED Glowing RED LED:- Battery is fully charged Glowing GREEN LED:- Battery is usable Glowing RED LED:- Need charge or it is not usable.
