**555 timer based PWM LED dimmer**
This project uses PWM to turn on and off a LED (or a strip of them) really fast and changes the duty cycle (Fig.1) so that the human brain perceive it as the dimming of the LED(s). This means that the MOSFET doesn’t have to drop large amount of voltage, this makes the device very energy efficient.
A simple but flawed idea to make a fixed frequency variable duty cycle oscillator based on a 555
timer and using the push-pull output to drive the RC timing through two routing diodes, a pot and a
series resistor to limit the min/max duty cycle to something sensible at around 9%/91%.
If the diode drops were negligible and the 555 timer output pulled fully up to VCC and down to
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.
By: Tyler Le
This circuit will power a small DIY induction smelter. The induction coil, coil power, and circuit power will all be external. In addition, this circuit has been tested on [ www.falstad.com/circuit/ ] and it seems to work great.
Within the circuit, U1 (a 555 timer) will create an adjustabl...