Lacerta PWM Dimmer for LED Flat-Field Box and Fans incl. Cable

Lacerta Dimmer for the control of the LED flatfield box

For the control of a FlatFieldBox (FFB) illumination for astronomical CCD cameras we need a flicker-free illumination AND an extremely short exposure time in the (sub-)millisecond range. Unfortunately, conventional dimmers cannot be used for this, but only a so-called PWM with a switch-on and switch-off frequency of 25 kHz or even faster!

What is PWM:
Theoretically, it would be sufficient to reduce the voltage by means of a resistor if we wanted to dim not LEDs but incandescent lamps. However, we absolutely need a dimmer with pulse width modulation, which controls the time interval in which the full voltage takes effect: the controlled instrument is switched off and on in quick succession.

Depending on the off/on frequency, various accessories can be operated: for a dew heating sleeve, switching on and off once per second or even less frequently would be sufficient because it is very sluggish. In everyday life, about one hundred cycles per second are sufficient for such dimmed LED light sources (e.g. living room lighting), because the human eye can hardly perceive the flashing any more from a frequency of 25 Hz. For FlatFieldBoxes (FFB), which were built for astronomical CCD cameras, at least 25 kHz are required to guarantee a uniformly illuminated surface even in a short exposure time.

Note: The dimmer can also be mounted in the opposite direction. However, as it cannot dim in this case, it must be reversed. Further information can be found under the "Reviews" tab.

COMMON USAGE ERRORS - PLEASE AVOID:

If the dimmer is mounted the other way round, it cannot dim but will not damage the FlatFieldBox. If you notice that you cannot create a dimming effect and/or the FlatFieldBox lights up even when the dimmer is switched off, you have most likely mounted the dimmer the wrong way round. In this case, please simply mount it the other way round instead of sending it back. The cable end with the RCA plug is the OUTPUT to the FlatFieldBox.

2. If the dimmer does not control the FlatFieldBox at all, please check the power supply. The dimmer will not work under 5 V INPUT, the recommended voltage is 12 V. Please note the polarity of the INPUT plug 5.5/2.1 mm: The pin in the middle is positive! Overvoltage or reversed polarity (whether input or output) can cause irreparable damage and is not covered by the warranty.

3. The dimmer is neither waterproof nor snowproof, please protect it from moisture and mechanical damage! Kinked cables, damaged housings and moisture-related malfunctions are not covered by the warranty. You can put the electronics in a plastic cover in the event of snowfall, but never leave it lying on a snow- or water-covered field.

4. Do not connect the dimmer to your stereo system or other audio equipment! Even if the plugs fit, this does not mean that they are intended for each other. You could damage the dimmer or your expensive system. Improper use is not covered by the warranty.

Safety informations: PDF Download