Potentiometer with and without a 555 timer

Following the led dimmer circuits in the Potato Gun Review for the LED transmitter:

http://www.reuk.co.uk/wordpress/lighting/led-dimmer-circuit/
http://www.electroschematics.com/9730/high-power-led-dimmer/
http://www.555-timer-circuits.com/led-dimmer.html





we have for the most complex:

We can build the simpler circuits with parts from the most complex. A parts list for all possible combinations:

Description	Mouser Part #	Link
Aluminum Electrolytic Capacitors - Leaded 470uF 16V	667-ECA-1CM471	http://www.mouser.com/ProductDetail/Panasonic/ECA-1CM471/?qs=sGAEpiMZZMvwFf0viD3Y3b8LTtskkwos%252bTZXzcHN%2fcU%3d
Darlington Transistors DARLINGTON TRAN	511-BD679	http://www.mouser.com/ProductDetail/STMicroelectronics/BD679/?qs=Djavi1aLnwpKhd3pF0IRIQ%3D%3D
MOSFET N-Channel 50V 33A	512-BUZ11_NR4941	http://www.mouser.com/ProductDetail/Fairchild-Semiconductor/BUZ11_NR4941/?qs=sGAEpiMZZMshyDBzk1%2fWi7Fu3l2zlAhYfCbfnrSmGYg%3d
Potentiometers Sgl Unit Vert Flat Snap-in 10K Ohms 20%	688-RK09L1140A2U	http://www.mouser.com/ProductDetail/ALPS/RK09L1140A2U/?qs=sGAEpiMZZMtC25l1F4XBU3JeeCo7XMTlNRqBfUrZdf0%3d
Diodes - General Purpose, Power, Switching 100V Io/200mA BULK	512-1N4148	http://www.mouser.com/ProductDetail/Fairchild-Semiconductor/1N4148/?qs=sGAEpiMZZMvplms98TlKY2CxbJu22D5%2f%2fpqXqVsMprg%3d
Diodes - General Purpose, Power, Switching 100V Io/200mA BULK	512-1N4148	http://www.mouser.com/ProductDetail/Fairchild-Semiconductor/1N4148/?qs=sGAEpiMZZMvplms98TlKY2CxbJu22D5%2f%2fpqXqVsMprg%3d
Metal Film Resistors - Through Hole 2watts 1Kohms 5%	594-5083NW1K000J	http://www.mouser.com/ProductDetail/Vishay-BC-Components/PR02000201001JR500/?qs=sGAEpiMZZMtlubZbdhIBIDWIPK23CRbllZqljMtzpi4%3d
Metal Film Resistors - Through Hole 1/10watt 47ohms .1% 50ppm	71-RN55C-B-47	http://www.mouser.com/ProductDetail/Vishay-Dale/RN55C47R0BB14/?qs=sGAEpiMZZMtlubZbdhIBIOj4GQCFpror65Ok4ODdEZQ%3d
Multilayer Ceramic Capacitors MLCC - Leaded 100000uF 200Volts	598-M30R104M2	http://www.mouser.com/ProductDetail/Cornell-Dubilier-CDE/M30R104M2/?qs=sGAEpiMZZMsh%252b1woXyUXj%2fb0PP%2fSr87QgLKMgW7U1AY%3d
Multilayer Ceramic Capacitors MLCC - Leaded 10000uF 50Volts	598-M15R103M5	http://www.mouser.com/ProductDetail/Cornell-Dubilier-CDE/M15R103M5/?qs=sGAEpiMZZMsh%252b1woXyUXj%2fb0PP%2fSr87QM%252b8hGV4CQBc%3d
Switch Mode Power Rectifiers 16A, 35 and 45 V	MBR1635,MBRB1645,NRVBB1645	http://www.onsemi.com/pub_link/Collateral/MBR1635-D.PDF
Standard LEDs - Through Hole LED PMI	696-SSL-LX5099IEW	http://www.mouser.com/ProductDetail/Lumex/SSL-LX5099IEW/?qs=sGAEpiMZZMtmwHDZQCdlqUPJk6OnVfwFh1MnnzvLabs%3d

The link describing the most complex 555 dimer circuit mentions the purpose of the 555 timer. It states that the 555 timer is not needed if you do not have more than one LED. Only a potentiometer is needed.

"Typically current is controlled using a resistor in series with the LED, or a current regulator circuit. Supplying more current to an LED increases its intensity, and reducing the current decreases its intensity. One way of dimming an LED is to use a variable resistor (potentiometer) to dynamically adjust the current getting to the LED and therefore increasing or decreasing its intensity. This works very well when just one LED bulb is involved."

"Unfortunately, all LEDs are not made equal – even those of nominally identical specifications from the same batch from the same manufacturer. Although this will not be apparent when strings of LEDs are being driven with the recommended forward current (e.g. 25mA for ultrabright LEDs), as the current is reduced some LEDs will turn off before others, and some will be dim when others are still quite bright etc."

-- http://www.reuk.co.uk/wordpress/lighting/led-dimmer-circuit/

So we could use this circuit instead:


With a subset of only these parts:

Description	Mouser Part #	Link
Potentiometers Sgl Unit Vert Flat Snap-in 10K Ohms 20%	688-RK09L1140A2U	http://www.mouser.com/ProductDetail/ALPS/RK09L1140A2U/?qs=sGAEpiMZZMtC25l1F4XBU3JeeCo7XMTlNRqBfUrZdf0%3d
Standard LEDs - Through Hole LED PMI	696-SSL-LX5099IEW	http://www.mouser.com/ProductDetail/Lumex/SSL-LX5099IEW/?qs=sGAEpiMZZMtmwHDZQCdlqUPJk6OnVfwFh1MnnzvLabs%3d