It is a square wave generator with a frequency meter for reading the generated frequency. As you can see from the wiring diagram, it is easily done as the LTC1799 integrated circuit takes care of everything. This integrated circuit has a range from 1 KHz to 33 MHz so by appropriately varying the values of the potentiometer and the relative resistance in series we can naturally obtain any frequency in the indicated range. There is also a divider inside the integrated circuit for 10 or 100 and therefore still have other possibilities: said divider can be deactivated or switched to +5 or ground to obtain the various functions. The frequency meter part is the same as the Freq project. 70 MHz with HP 2414 described elsewhere on the site. A few words about the power supply, naturally it can be powered with 8 - 12 V or as can be seen from the photo with 5 rechargeable elements: I preferred to use two voltage regulators, a 7805 for the frequency meter part and a 78L05 for the analogue part to avoid at most interference between the two circuits. The practical implementation does not present particular difficulties (perhaps the most challenging part is the soldering of the SMD chip) in addition to the fact that to keep the dimensions down I used a somewhat small container with related problems in arranging them all the components: for this reason the ignition and switching for the divider are carried out by visible jumpers between the two adjustment knobs.