http://falstad.com/circuit/circuitjs.html?ctz=CQAgjCAMB0l3BWcMBMcUHYMGZIA4UA2ATmIxEOxCQUgCgA3cMFEFFAFmdbBan46Q20MvyEwEdAObc2nWSjx4xdAE4L5KBITlchhePXVad7LidlDB8OgHdZvVhcds7bbbOyFlLoyC8+fAFs+Py4cHQALv6Q5vLBZvwAtBAwHHjEYAhK2pCEHMSQYFxJEggcCDicGMQcdekQ4W64ceYeifT2CYL+3mxKUM19isoj-cqd41Nj2F6D9jNzibM69AAmuv5zYAZbpuAAcpW8bjtCK55zky4XLhw7gzJ3eEIuCHzip3zpQmM-g9ELhx8lNgXpwCBStAEMRKMCiNlZpgBjBsBgUMUOBhILCUJksdsIvY7g8-g9JmTTAM6hM3H8Xr1lP96IC5mDGSB2a8xNA0Ri6tjcficDowES9pyQUDyc02Q9gvdVkMmfK+jT5hz-jDWP8UMr-HguAkUXQ0MRZIqLQzxLBDKkRN4CjiMOVCJwiBBPXTqaSBtgEKwKX6AzEjSHJi1-CHIxcI7EJRxsKxY25LdZObDOXANYnk2ykxzJgUqcp0b8TdFyka+trCxCoQL+QhsBk8IQsGRVtAxejsAUvFpsGLO8hJrX-axa2haepa29iE5Qq9DGOF7Iywo1CANy4N9OwoY3HvQnuTfZxyH28nw1EKOio6wNxP+PbaDVm4J3hgKlkqGV6rULooNgxBKMQSBipMp6lmgEpQbBwQbrmGpIQWtbIauyaGtQa4YVu6Fobh1rUDY55EUIGDYcyR5UQylFcOq9BMPRnLpNu2EtuCVhCEg4hQNCNFGthLG+IJ66waJ9jFlmViZmMY51JqBbBPQABmnIPOmCrZpmjQRAA9uA5ogtxpDCLxtqQJRLC8WwRn+HQhn+hQ4KCGZsEwIYnbaFoELXg5LZiPw5oAGr6QANpEACGUgAKZ0EAA https://www.reddit.com/r/electronics/comments/kln6y0/voltage_controlled_trianglesquare_wave_oscillator/