| ??? 01/02/03 19:18 Read: times |
#35439 - RE: Some questions |
"2. A common term - "Pull up resistor". What does it mean and how does it work? Does it "pull up" the current to a certain level?"
A pull-up resistor pulls up the voltage level. If for example you have a button between a port pin and ground, voltage level will go to zero when the button is pressed. To get the voltage level up again (and to have high level again on the port pin), you connect the port pin to Vcc. The pull-up resistor restricts the current (5V, 10k pull-up resistor -> 0.5 mA). "According to the electronic specs is looks like a bad idea to drive a led from the pins directly..(Am I right? Is a transistor the proper solution?)" Both right. The first is a bad idea, and the second is a proper solution. 3. What's the difference between a voltage regulator and a "operation amplifier"(in Swedish: operations förstärkare)? Is the voltage regulater fixed and the OP. Amp. variable with the two resistors?" A voltage regulator is an integrated circuit with a special purpose. An op-amp is a device, which is used in many ways depending on the connected devices (resistors, capacitors, diodes, ...): Schmitt trigger, integrator, impedance changer and so on. PS: I'm not sure how all these circuits are named in english. Regards, Jörg |
| Topic | Author | Date |
| Some questions | 01/01/70 00:00 | |
| RE: Some questions | 01/01/70 00:00 | |
| RE: Some questions | 01/01/70 00:00 | |
| RE: Some questions | 01/01/70 00:00 | |
| RE: Some questions | 01/01/70 00:00 | |
| RE: Some questions | 01/01/70 00:00 | |
| RE: Some questions - Jörg | 01/01/70 00:00 | |
| RE: Some questions - Jörg | 01/01/70 00:00 | |
| Thank you | 01/01/70 00:00 | |
| RE: Some questions | 01/01/70 00:00 | |
| RE: Some questions | 01/01/70 00:00 | |
| RE: one more thing... | 01/01/70 00:00 | |
| RE: one more thing... | 01/01/70 00:00 | |
RE: Some questions | 01/01/70 00:00 |



