Homework Statement
I am trying to use a slide wire potentiometer and a galvanometer to find the electromotive force of an unknown cell. I have heard that the balance point at which the galvanometer needle has zero deflection should be towards the centre of the slide wire as this reduces...
Hi, I'm trying to understand vortex shedding and how the Karman vortex street occurs when air flows around a cylindrical object, so far it's going OK but then I came across this part of the explanation which leaves me confused:
"Looking at the figure above, the formation of the separation...
I've found this http://www.ti.com/lit/ds/symlink/sn54ahc157.pdf to use as a MUX.
However, I'm confused about a few details:
1) What is the "Input clamp current" because I'm worried about the negative current there.
2) Do I need some sort of resistor on the Vcc to limit the current through the...
Ok, The 2 input multiplexer looks right, well at least the truth table on them seems to do what I'm looking for.
And the Raspberry pi won't be 'powering' the servo, the servo has 3 leads, one for +5V other GND and the third is the PWM control which is fine at 3.3V and can be controlled by the...
In which case, will something like this work?
http://imgur.com/vmcR53y
The diodes will prevent the current shorting to ground at the GPIO. The problem is still this negative voltage thing and also, in the simulation I'm only getting 2.8V over the servo resistance even when is is really high. Is...
I guess what I'm also asking is are there an alternatives to create a circuit which allows me to use two PWM signals to drive one servo with a way to select which source I use, if the MOSFET idea is bad.
http://imgur.com/UwkOqvX
The 300k ohm resistor represents the servo and the two "raspberry pi GPIO" on the side are the pins I will use to controll which device can send PWM signals to the servo. This will either be the RX (radio reciever) which will continuously transmit a PWM signal or the...
I need to use a P channel becuase the MOSFET will be controlling a PWM data line connected to a servo, so the load will always be on the GND side of the MOSFET. Is it only this specific one I cannot use, or P channels in general? Also, could you explain why this one is not going to work? Thanks...
Hi, I'm planning on using a mosfet with my raspberry pi to controll a circuit, using the GPIO pins which can be set to +3.3V or GND but I'm having problems with choosing the type of MOSFET I will need. I've found the data sheet for a possibility here
http://www.diodes.com/datasheets/ZVP3306A.pdf...
Hi, I'm looking for a device like a transistor which preforms the opposite. E.g.
On an NPN when Base is +0.7V current can flow through the Collector to the Emitter and when the voltage at B is 0V (i.e. a switch connected to base is open) no current will flow from C to E. I want the opposite of...
Hi, I want to use a digital ammeter to measure the current flow though a Raspberry pi. The Pi uses about 700mA and is 5V so its got a resiatance of about 7 ohms. Therefore something like 0.5 ohm ammeter will have a large voltage drop of about 0.3V which is way too large and would lead to the...