A very simple water level indicator electronic circuit project can be designed using the ULN2004 high voltage, high current darlington arrays that contain seven open collector darlington pairs with common emitters . Each channel rated at 500mA and can withstand peak currents of 600mA.
This ULN2004 water level indicator is very simple and require few external electronic parts . As the water level rise in the tank , it comes in contact with probes P1 through P7 and thereby makes pins 7 trough 1 high sequentially . The corresponding output pins 10 trough 16 go low one after other and LED1 through LED7 will light up . When water comes in contact with the last probe P7 , the buzzer connected to the last pin 16 will sound . The circuit is very simple and does not require any settings .
This electronic circuit project must be powered from a fixed output DC voltage that will provide an output voltage between 9 and 12 volts .
A very simple ultrasonic parking system can be designed using this electronic circuit project . This ultrasonic parking system uses few common electronic parts like :transistors, resistors, capacitors and diodes .
As sensors in this electronic circuit project is used two piezoelectric element that must be mounted in “V” like in circuit diagram . When an object is closer to the sensor , a 3kHz sound will be generated in BL speaker . UW1 and UW2 piezoelectric sensors must be mounted at 70cm distance one from another .
This circuit project must be powered from a simple 12 volt DC power supply circuit .
This Video amplifier electronic circuit project is based on the wideband 3-channel video amplifier IC manufactured by New Japan Radio Co. Ltd.
The NJM41045 video amplifier is suitable for the HD video application because of -3dB large-signal bandwidth of 400MHz.
The circuit can be powered entire from a single or dual power supply circuit , supporting an input voltage range between 4.5 to 9.5 for single power source and from +/-3 to +/-5 volts for dual power source .