led fm scale

With home-made FM-tuners, the design and construction of the tuning scale often causes much brain racking. A mechanical solution is excluded from the very beginning because of the con-structional difficulties. In many cases the only option left is a display of the tuning voltage (in the case of varicap tuners) by means of a voltmeter with its scale calibrated in frequency. A Siemens IC type UAA 170, together with a few external components, pro-vides an electronic scale. The table shows the relationship between tuning voltage, frequency , and LED read-out. Only one LED is lit at any time