Description : Connect the Components as shown in the circuit. In this circuit, according to the Heat on Thermistor, the Buzzer will sound like alarm. This is because, when the Thermistor gets heated a voltage passes to the Base of the Transistor and the  Junction between emitter and collector gets connector and Buzzer will be ON.

Diode is used here to prevent back Emf. Hence HEAT SENSOR Module  is ready. Pin Diagram of BC548 : USB tester: This project will be useful to check the output of your USB device like computers USB port etc.The green LED will indicate whether it is working or not.

It will be useful to have it in your mini lab or hobbyists garage. Simple USB tester Components Needed : * The PCB -  you ca make PCB on your own by method called ironing. the PCB layout has been given below * The USB connector – You can buy new USB connector or else remove the connector from unused USB connector. * Two 22K resistors * One 1k resistor * One 100 ohm resistor * One 1. 5 k resistor * One 3v3 zener diode * One 1N4148 diode * Two leds (green and red) Circuit :USB-tester circuit schematic The circuit logic is simple.

The operation is simple, After you connect it to the USB port, if it is working fine then green LED is lit with full intensity and you will have a message from your operating system telling you that the USB has been detected. If the polarity is reversed the red LED is lit with full  intensity. Any other combination causes lit one of the two LED but very dim. PCB board Layout : usb tester PCB board layout Components Connection : USB-Tester-Soldering-components Complete Project : USB-Tester