vactrol.md

@@ -47,3 +47,11 @@ The cylindrical 5mm green LEDs I found were Kingbright WP483GDT which cost ~0.30
 
 ### Light isolation
 Once glued together one should isolate outside light from entering the fixture. There are different ways to do this. One could use one or more black heat shrink tubes (which have the problem of letting light in at the front) or  dip the fixture into black liquid plastic.
+
+## Circuits
+
+### Super simple passive LPG
+![LPG_passive](/uploads/89d85802c26e973b928e601951bf2b88/LPG_passive.png)
+
+### Sallen Key LPF with variable Decay
+![Sallen_key_LPG](/uploads/a825240c4fc4d9bc108134327ddc8f7c/Sallen_key_LPG.png)
\ No newline at end of file