This simple circuit can be used to emulate the operation of a music box. The number of notes may be limited to 10 at the most, and therefore is capable of generating a simple melody. By: Akanksha Rathode Circuit Operation The circuit uses two popular integrated circuits: The timer 555 and 4017 decade counter Operation […]
Newly Updated Circuit Projects:
Extended Telephone Ring Amplifier/Repeater Circuit
The discussed phone repeater circuit can extend the range of your land line ring sound from the phone such that one is able to make a call heard in another room or even in another house. By: R.K. Singh Circuit Operation The circuit can be connected with an attached buzzer, the buzzer with a driving […]
Simple Thermostat Circuit Using Transistors
The electronic thermostat explained here can be used to control the room temperature by appropriately switching (turning on and off) a heating device. By: R.K. Singh Operational details of electronic thermostat The circuit employs a thermistor NTC (negative temperature coefficient) as the sensor device. – As long as the ambient temperature stays higher than the […]
Power Interruption Alarm Circuit for Instant Power Failure Indications
This power interruption alarm circuit will alert you whenever there’s a power failure or an interruption in the mains. In some special conditions it becomes imperative to know whether the mains that powers some important system or circuit is absent. By: Manisha Patel How the power failure alarm works This proposed circuit is connected to […]
Differential Temperature Detector/Controller Circuit
The circuit identifies and detects the temperature difference between two sensors and activates a relay when the temperature is not identical on these differently positioned sensors. By: Manisha Patel It’ll also enable you to detect a difference in temperature, although the temperature sensing devices can be set are discretely, using a potentiometer. Operational Details To […]
4 LED Temperature Indicator Circuit
The 4 LED temperature indicator circuit discussed here is very useful for getting a visual information regarding the state of temperature which is to be monitored. Circuit Operation In the circuit temperature status is displayed using four LEDs. – A green LED, indicating that the temperature is in the desirable level- Two yellow LEDs are […]





