This simple water level indicator will activate a buzzer in order to make a noise when a certain level of water is being reached. Because the water sensor and the command circuit are located on the same printed circuit board, indicator, together with its 9 V battery and the buzzer can be mounted in a compact case. Obviously the sensor, that is made by corossion, on the board, must not be mounted directly on iron or steel bathtubs but with a magnet atached on the case. Check out the new water level sensor circuit.

This simple water level sensor circuit monitors the presence of water in a certain location or container. The circuit sends an acoustic alarm when it senses a drop of water leak. It is very simple to build and it is made of a single IC and some passive components. Check out the water level indicator circuit too!

This peak indicator circuit signals thru 2 led’s the exceeding of a pre-estabilished value of any stereo audio channel.
Signals from the 2 channels are rectified (monoalternance) with D1 and D2 and the resulted voltage is applied on OA IC TLC272 inversor entries.
The peak indicator circuit can be used up to 20kHz frequency and the current consumption with led off is 0.25mA and with both leds on is 24mA.

A RF probe is a circuit of test equipment that converts a high frequency signal to a DC voltage. In this way it is very easy to measure RF voltages for either testing or adjustment transmitters, receivers, modulators.

The RF probe circuit described here is suitable for signals in the frequency range from about 100 kHz to 1000 MHz. Although the diode used here can, in principle, go up to 3 GHz, the impedance of the ground connection will adversely influence the measurement at such very high frequencies. Also, please keep in mind to use this probe only on low RF power.