# Legendary LM311 comparator - addition for STM32 discovery/nucleo for L/C measure #
![LM 311 LC meter.jpg](//image.easyeda.com/pullimage/7Okxq5DykgHnCnwNFLRkTub2UYa9Lmh6a4129xz4.jpeg)
![disco sh plus lcm merged top.jpg](//image.easyeda.com/pullimage/LQC1eyRJZIRFOzxIL3IuzkEtYxhQRH4rhLdPK3nV.jpeg)
![disco sh plus lcm merged bottom.jpg](//image.easyeda.com/pullimage/QNkrlEUThEK3aEwsCeKzoxJosEpS...
LM393 Low Power Dual Voltage Comparators DIP-8 test circuit.
Very inexpensive and a good way to learn about OpAmps. Needs 9 volts to operate.
Switch not in schema or PCB, added while building.
Zip file contains a short video of the circuit working.
Tested with DBL358, IR3F02, IR9082, IR94558, JRC4558D, NE5532, KIA393P, HA17393
![enter image description here]
![enter image de...
A simple demonstration of the TLV3501 comparator:
using the EasyEDA Spice symbol and the spice .subckt model from:
A simple LM324 squarewave and sawtooth generator with triangle to adjustable duty cycle pulse output.
Triangle output is roughly linear by being set to a small section of an exponetial charge and discharge.
**How it works:**
The actual oscillator is made up of the components around U2. See "Figure 27. Squarewave Oscillator" in: http://www.ti.com/lit/ds/symlink/lm124-n.pdf
U1 just gener...
Water detector with 4 level stages. Each stage makes the 555 timer to give a supply period for the buzzer. The active buzzer transmits sound with a pause period between 0.5-3 seconds, depending on the level detected.