I've been unable to get my nrf24l01+ modules to talk to each other (each one is attached to an Arduino UNO). I am definitely using 3.3V and have verified the wiring many times. I've seen many people recommend soldering a capacitor between GND (pin 1) and VCC (pin 2) on the modules (to even out a spotty power supply).
I have several 10uF tantalum capacitors lying around (one lead is longer than the other one). My question is: does it matter which capacitor lead goes to GND and which one goes to VCC?
Thank you in advance for what I am sure is a n00b question.
Tantalums and other electrolytics must be connected the right way round. Usually there
is a stripe on the +ve lead, but consult the datasheet for definitive information for your
capacitor (some have a + symbol for instance).
Lead length is not a standard, different manufacturers may use different conventions.
Latency:
I've been unable to get my nrf24l01+ modules to talk to each other (each one is attached to an Arduino UNO). I am definitely using 3.3V and have verified the wiring many times. I've seen many people recommend soldering a capacitor between GND (pin 1) and VCC (pin 2) on the modules (to even out a spotty power supply).
I have several 10uF tantalum capacitors lying around (one lead is longer than the other one). My question is: does it matter which capacitor lead goes to GND and which one goes to VCC?
Thank you in advance for what I am sure is a n00b question.
I wouldn't use tantalum. For what you want, something like a 0.1 uF ceramic cap, with leads absolutely as short as possible, should do what you need.
Or, use the 0.1uF and maybe a 10uF or so aluminum electrolytic (both caps in parallel). The 0.1 handles the high frequency noise and spikes, and the 10 uF is a "surge tank" to protect against positive surges and make up for negative surges.
If your boards have 2.54mm (0.1 inch) pin spacing, and hopefully the VCC and GND are right next to each other, take the 0.1uF cap, cut the leads to something like 3mm of so and solder it DIRECTLY to the power and gnd pins.
Thank you for the responses everyone! Right now the only capacitors that I have are 10uF tantalum capacitors. I'll order the ceramic ones you suggest but you would you please look at this image and let me know if I've done everything correctly?
Your connections look OK. These days you no longer need to choose between the high capacitance of an Electrolytic with the low ESR of a ceramic. There are 10uF Ceramics available for pennies.
rmetzner49:
Your connections look OK. These days you no longer need to choose between the high capacitance of an Electrolytic with the low ESR of a ceramic. There are 10uF Ceramics available for pennies.
In college, in one of the labs, we plotted the grid voltage vs plate current of a 6C4 triode - by hand - on graph paper - using a high voltage (around 150v) power supply, a pair of analog multimeters (one for grid voltage, one for plate current) and a potentiometer to adjust the grid voltage from if I recall some 15 volts negative to 5 to 10 volts positive (i.e. cutoff to saturation). Ahh the good old days (were they really good?)
