FM receiver TDA7000 continuous loop scan

Discussion in 'The Projects Forum' started by brickman7, Sep 29, 2013.

  1. brickman7

    Thread Starter New Member

    Sep 29, 2013
    New to electronics design, computer tech needs a schematic based on the simple TDA7000 ic to continuously scan through the frequencies! I have the TDA7000s, and YDA9088s but they are surface mounts. I can get most older ICs from a supplier in China so I'll take suggestions. I just need it as simple as possible. I have TDA2822s for amps, but I can get what is needed. I also have BB910 varactor diodes.

    I just need an fm scanner to scan thru the frequencies and not lock on a station without having to be reset to continue scanning. And output thru an earphone and speaker. Also, I do not want to mute the scanning process. I need to hear the white noise as it scans.

  2. Dodgydave

    Distinguished Member

    Jun 22, 2012
    Here is a circuit of a TDA7500 receiver using a varicap diode, you need to put a sweeping dc voltage instead of the wiper of the 100 k tuner pot, to scan through the wave band.

    I would remove the 100k preset and use a triangle wave ramp generator like a 555 timer set to .1Hz to 0.5hz and buffer the the voltage across the charging cap to feed into the varicap diode.
    Last edited: Sep 29, 2013