The following is a partial picture of the improved FM6688 electrical schematic diagram and the polishing circuit and the matching FM transmitter circuit diagram after the TDA7088T classic circuit and FM6688 radio mapping!
FM6688 radio electric schematic after polishing:
Note: The T1 tube in the figure is a high-frequency amplifier added by the moderator, which can greatly improve the sensitivity of the FM receiver. Before the transformation, the weaker signal station has strong directivity, slightly
When you turn around, there will be noise or even normal listening! After polishing, several radio stations were added, and the sense of direction was basically gone! Because the FM6688 radio space is too small, so
T1 try to choose patch high-frequency transistors, you can also choose sesame-shaped high-frequency transistors, such as BFR96, you can also choose cheap ordinary 9018 high-frequency transistors (slightly less effective).
In addition, if you want to reduce the impact of the FM radio on the 6688 battery standby time, you can remove the power indicator light. I personally think that this light is not very useful. And the use of the lamp may
To reduce the standby time by 1/5!
The circuit diagram of the FM transmitter made by the moderator:
The transmitter is used with FM6688 radio, the effect is good, and the method of use is also extremely simple:
Insert a 3.5mm dual-core plug at one end into the machine to automatically turn on the power of the FM transmitter. The lotus plug at the other end can be inserted into the AUDIO L or AUDIO R line of the TV.
Out of the socket, turn the TV volume to the minimum or simply mute it. Turn on the FM6688 radio and press the search button to automatically search for the program being broadcast on the TV.
Received TV sound from the transmitter within the range of square meters. Of course, you can also use the audio output port of other audio equipment, such as the headphone output port, but you need a
Change the plug. At this time, when the headphone port of the playback device is plugged in, the internal speaker is automatically turned off, the volume is adjusted appropriately, and you can also enjoy the convenience and entertainment brought by the self-run FM radio station. Connect this power
Road uses an ordinary AAA battery, can be used for one year!
Disassembled FM6688 radio:
Polish the traces of FM6688 radio:
Increase the volume adjustment, switch:
How to use FM transmitter:
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