| ??? 03/01/06 12:59 Modified: 03/01/06 13:01 Read: times |
#110970 - piezo impedence Responding to: ???'s previous message |
Hi
piezos are very hi impedance devices. The art of designing a sensor is not to "load" the device you are sensing. So a FET may be in order as they have very high imput impedances but you need to protect the input from over voltage. If you but the 2 terminals on the piezo a cross an CRO you will see how high the voltage gets (but a 1M resistor in parallel 1st and well as a 30V TVS... so you don't overload the CRO).... you may need to tap or bang the piezo to get it to produce voltage. The wave form of a an excited piezo will be very quick... so you may need a one-shot cct to "strech the pulse" before the micro can see it. JG |
| Topic | Author | Date |
| High voltage input | 01/01/70 00:00 | |
| High voltage input | 01/01/70 00:00 | |
| Isolated supply | 01/01/70 00:00 | |
| Interrupts | 01/01/70 00:00 | |
| Interrupts | 01/01/70 00:00 | |
| HT | 01/01/70 00:00 | |
| piezo impedence | 01/01/70 00:00 | |
| Unidirectional transzorb, separation | 01/01/70 00:00 | |
| > Could you solve the problem? | 01/01/70 00:00 | |
More or less | 01/01/70 00:00 |