Description: Simple CircuitComposed of only commonly used triodes and resistor capacitors inductors, without an audio transforming, and is easy to make. The variable capacitors uses a double variable capacitors, and the two are connected in parallel to obtain sufficient capacity. The double sided board circuit is used, the board base is made of fiberglass material, and the actual thickness is about 1.5~1.6mm.Good Sound QualityThis transmitting works very well within the effective distance (0.5~1 meter), with high sound fidelity, especially when listening with a direct playing radio and high impedance dynamic headphones, the sound quality is not much different from the effect of direct playback by the player.Easy to UseNo external antenna is required (medium wave requires tens of meters), and the field leaked by the rod affects the receiving completely, which is easy to implement and the transmitting distance is relatively short.Multiple InterfacesThere are many interfaces, including waveform test terminal, audio socket, external power socket, etc., which are easy to use and expand functions;Wide UseCan be connected to an external power supply or installed with a power supply for self standing use.This Set uses fully discrete circuits, which is particularly suitable for students to learn working principles, practice production and testing. Specification: Rate range: 525~1605kHzPower supply voltages: 6VTransmitting distance: about 1 meter for superheterodyne medium wave radio, about 0.5 meter for direct radio.The transmitting is equipped with a 3.5mm headphone signal cable, without batteries. Size Chart: 78mmx85mm/3.07inchx3.35inch Package Includes: 1 Motherboard, 1 Audio Cable, and 1 Manual Note: Please allow slightly errors 1-2cm differences due to manual measurement.