76-108MHz Adjustable Frequency FM Radio DIY Kit Volume Control With Power Switch Soldering Practice Kit Electronic Teaching

Features:
1. This circuit includes all the functions of FM radio receiving frequency discrimination output audio signals from the antenna, as well as a search and tuning circuit, signal detection circuit, squelch circuit, and a frequency locked loop FLL circuit with frequency offset in compression.
2. High success rate: This kit optimizes the arrangement of various components, making it easy to install and manufacture with a very high success rate.
3. This kit is not only for welding and assembly, but also for adjusting and winding coils by oneself, which is more fun and suitable for beginners, especially students or enthusiasts who are using welding tools for the first time.
4. The frequency range is wide, with a frequency modulation range of 76-108MHz wider than the common range of 88-108MHz. It can receive both general FM stations and campus radio stations.
5. The intermediate frequency of the circuit is designed to be 70KHZ, and the peripheral circuit does not require an intermediate frequency transformer. The frequency selection is completed by the internal RC intermediate frequency filter of the circuit.
6. Support radio memory function, automatically restore the radio and volume from the last shutdown when turned on next time.

Parameter:
Working voltage: 1.8~3.6V
Frequency range: 76~108MHz
Battery box model: 1.5V AA (2 cells)
PCB board size: 56mm * 30mm
Operation method:
This machine uses electronic tuning buttons (SEEK+, SEEK -) like a digital tuning radio, as well as volume control buttons (VOL+, VOL -) and power switch buttons (PW). After the circuit is powered on, press the power switch button once, and the circuit will start working. Press SEEK+to search for the radio station at the high-end frequency or SEEK - to search for the radio station at the low-end frequency. The radio station signal will be automatically searched and the tuning will stop automatically. If you continue to press the search button, the circuit will continue to search for the radio station.

Welding sequence:
1. First, solder the surface mount components
2. Then solder in the following order: 1. Resistance 2. Inductance 3. Capacitor 4. Diode 5. Button 6. Earphone socket and switch.