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DanyR
DanyR il y a 12 heures
This is indeed a solution for a 2 live wire situation. Thanks very much!
Mains Power Driver by MCU DC or PWM
BreedJ
BreedJ il y a 17 heures
Hi Sven, Here are some things I can think of which might solve your problem.   Check if there is no short circuit between the pins of the IC since its difficult to solder. Check if there are no other SMD components shorted. Some of the components may change the linearity if they are shorted. Are you sure the power source or measurement device you checked it against is linear? I mean are you sure the -50dBm is actualy -50dBm. Do you use 50 Ohm impedence cables and connectors. If you use a scope to check the voltage, did you use a 50Ohm terminator of the 50Ohm option of your scope, Are the cables connected properly. Is the reference voltage what it should be? The IC might be damaged or bad. In the past I bought some from AliExpress. Some of these components, like the voltage reference where no good. I hope this will help. Best regards, Joost
RF Power Meter with 1MHz-10GHz bandwidth and 55dB dynamic range
Claus Wahl
Claus Wahl il y a 1 jour
Exactly, oetelaarNG. To make it simple and either intuitive (pull the handle should be ok) or well guided.  I believe that Elektor needs to better explain what could be done to the exterior and what is not OK. Could the door have a drilled hole? Could a well integrated screen be recessed in the door or the frame? If no modification at all is allowed on the exterior, most of the suggestions are breaking the 'design rules'. It seems like a camera is out as it will have to be wisely placed? Even a voice-system will be difficult. We still have knocking and pulling the bell, but advanced use of these inputs *will* require some guiding for the visitor, eg with a note. But then, why not make a nice naming plate with some touch input and communication device? If some form of recessed mounting could be accepted: Occasional users, old folks etc should be comfortable using it: Pull the handle, activate a screen with info and touch/keys and place the call. When not in use, the overall color and appearance match the door or frame.  
Invisible Multi-Target Doorbell
karim rihani
karim rihani il y a 1 jour
Lead Acid Battery charger 
Battery Charger Next Generation: request for comments
Bastelfix
Bastelfix il y a 1 jour
Hy! I build the unit and it works. But i have a problem with the linearity. For example: i used a calibratet RF Power Source for calibration. -calibration at 140MHz and RF Level-20dBm -calibration saved now the following measurement when changing RF Level at the input (all without attenuator) : RF Level at Input:                Display Power Meter: 0 dBm                                     -11,0 dBm -5 dBm                                    -13 dBm -10 dBm                                  -15 dBm -20 dBm                                  -20 dbm   (calibration point) -30 dBm                                  -24 dBm -40 dbm                                  -28 dBm -50 dBm                                  -32 dBm What could be the problem? Is there a conversion factor not correct? Best regards, Sven
RF Power Meter with 1MHz-10GHz bandwidth and 55dB dynamic range