fixed link

README.md

@@ -84,7 +84,7 @@ Electrically seen, the frontend consists of two ring oscillators for temperature
 
 Each ring oscillator is formed by 3/6 of a [74HCU04](https://assets.nexperia.com/documents/data-sheet/74HCU04.pdf) Hex Inverter `U205`. Three inverters are connected in series. The first and third inverter are feedbacked directly via an RC series element `C207`/`R210`, `R214`/`C215`, `C208`/`R211`, `R215`/`C216`, the entire ring oscillator via a capacitor `C212`, `C213`. Both ring oscillators can be pulled to +3 V by a P-channel MOSFET `Q201`, `Q202` at the first inverter with separate control, which corresponds to ground at the output, to deactivate them. The heating resistors for the reference, which can be activated by closing `Q203`, `Q204` with closed P-channel MOSFETs `Q201`, `Q202`, are also located at the input of the inverters.
 
-The feedback path for the temperature measurement consists of 2/3 buffers of a [74LVC3G34] (https://assets.nexperia.com/documents/data-sheet/74LVC3G34.pdf) `U207` and two resistors `R219` and `R223`, which probably are used for the fine tuning of the resonance frequency. This is followed by four single pole single throw (SPST) switches [TS3A4751](http://www.ti.com/lit/ds/symlink/ts3a4751.pdf) `U201`, the NO of which is connected to the output of the buffer and which each switch one of the four possible measuring resistors (temperature/humidity/Ref1/Ref2) into the feedback path. The measuring tap is located between buffer and switch with a series resistor `R224`.
+The feedback path for the temperature measurement consists of 2/3 buffers of a [74LVC3G34](https://assets.nexperia.com/documents/data-sheet/74LVC3G34.pdf) `U207` and two resistors `R219` and `R223`, which probably are used for the fine tuning of the resonance frequency. This is followed by four single pole single throw (SPST) switches [TS3A4751](http://www.ti.com/lit/ds/symlink/ts3a4751.pdf) `U201`, the NO of which is connected to the output of the buffer and which each switch one of the four possible measuring resistors (temperature/humidity/Ref1/Ref2) into the feedback path. The measuring tap is located between buffer and switch with a series resistor `R224`.
 
 In the feedback path of the humidity measurement there is a circuit formed by the remaining buffer and two resistors `R226` and R220. The measuring tap is made exactly like in the temperature measurement by a resistor `R225`. Furthermore in the feedback path there are three SPDT switches [TS5A9411](http://www.ti.com/lit/ds/symlink/ts5a9411.pdf) `U202-204`, which switch the measuring and reference capacitor either into the feedback network or to ground. U205 has no connection between COM and the input of the first buffer, where there should normally be a reference capacitor, so this switch does not serve any obvious purpose. However, since it is driven in software like the other two, it can be assumed that the switches have an example-independent non-linear effect on the feedback frequency measured at this switch to compensate for it. Parallel to the switches, fixed feedback is applied via the resistor `R212`.