S-meters have gained well-deserved popularity due to the fact that they do not require constant calibration, which significantly simplifies the measurement process itself. The calibration or auto-calibration operation as such is not necessary. The accuracy of the measurement is determined only by the accuracy of the selection of resistor values and the sensitivity of the Comparators. S-meters with led indicators are very attractive from the point of view of ergonomics and design, convenience of visual control.
The proposed version of the automatic led S-meter with unipolar power has 10 levels of reference and is extremely simple due to the use of affordable and inexpensive chip LM3914 (LM3915, LM3916). This chip, a specialized controller for controlling linear led scales, has everything we need-a precision ten-step voltage divider with a linear division step of 0.1, ten Comparators, and an led control circuit.
The LF voltage from the receiver or transceiver at the input of the device is regulated by a tuning resistor, setting the required input level.
Switch S1 determines the mode of operation of the scale – if closed - a luminous column, if open-a luminous point, i.e. only one significant led is lit.
This device can be used as an S-meter in receivers and transceivers, instead of switch devices. Power supply of the device is 12V. the set Includes: documentation, printed circuit Board size 4x39 mm, lm3914 chip (LM3915, LM3916), LEDs or led matrix, capacitors and resistors.
We offer a choice: the Board is made for the installation of a 10-bit led matrix or 10 LEDs with a diameter of 3 mm.