Product description: This kit uses fully discrete circuits, which is especially suitable for students to learn working principles, practice production and test; Variable capacitors use frequency modulation and amplitude modulation quadruple variable capacitors, and connect two amplitude modulation couplings in parallel to obtain sufficient capacity. The quadruple is the common 223P AM double-connected variable capacitor, and feels better; The circuit board base is made of glass fiber material, the thickness measured is about 1.5~1.6mm,the single-sided green/butter white lettering, the pad is sprayed with tin,and can be directly welded without grinding; The manual contains circuit schematic diagrams and circuit board diagrams, as well as debugging methods and experience under amateur conditions. If you need more information and professional debugging methods, please download or refer to relevant professional books on the Internet; Main characteristics of finished product: 1. Frequency range: 525~1605kHz; 2. Power supply voltage: 6V; 3. Circuit board size: 78mmx85mm (length x width); 4. Transmitting distance: superheterodyne medium wave radio is about 1 meter, direct-type medium wave radio is about 0.5 meter The circuit board obtained by the buyer may be slightly different from the sample in the picture, mainly due to the change of component position and the same circuit structure. This product has been modified and perfected n times from trial-produced samples to products sold (mainly to modify the wiring of the circuit board), and is still in continuous improvement. Usually minor insubstantial modifications, such as slight movement of component positions and minor wiring adjustments will not change the version number, and will not re-photograph and upload, hereby declare; The transmitter board is equipped with a 3.5mm headphone signal line, and the battery-powered board is optional and non-essential, without batteries. Medium Wave Transmitter 525~1605kHz For FM finished Radio Note: this is a DIY kit, all the parts need yourself to solder it. [Features] 1. The circuit is simple. It is only composed of commonly used triodes and resistance-capacitance components, without audio transformer, easy to make; 2. The sound quality is good. Within the rated transmission distance, the sound quality is close to FM broadcasting, and the signal-to-noise ratio is good, especially the effect of receiving with a repeater is not much different from that of direct broadcasting of the modulated signal; 3. No external antenna is needed (medium wave needs tens of meters), and the receiver is completely affected by the magnetic field leaked by the magnetic rod, which is easy to implement, but the transmission distance is relatively short; 4. There are many interfaces, designed with levels of transistors, quiescent current test , and external power sockets, which are easy to use and expand functions; 5. It can be used with an external power supply, or it can be used independently by adding a battery pack module (battery power supply board). Color: As Shown Material: PC+metal Package Contents: 1 x Medium Wave Transmitter(Finish Board) Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.