Testing diode ckt

[Tom Sanders]

Hi,

I am trying to figure out how the circuit shown below works.
resistor
Vdc(0-5)----/\/\/\/\-----------------
| |
| |
______ ____
/ \
_______ / \
(capacitor) | ------ (diode)
| |
| |
--------------------
Gnd

I would greatly appreciate it. I am not sure how this circuit works.
How can this circuit be tested?

 

[Watson A.Name - \"Watt Su]

"Tom Sanders" <engrwebmaster@yahoo.com> wrote in message
news:fc4f9f5.0406161307.1d0a5a1e@posting.google.com...

Hi,

I am trying to figure out how the circuit shown below works.
resistor
Vdc(0-5)----/\/\/\/\-----------------
| |
| |
______ ____
/ \
_______ / \
(capacitor) | ------ (diode)
| |
| |
--------------------
Gnd

I would greatly appreciate it. I am not sure how this circuit works.
How can this circuit be tested?

The diode is reverse biased because the inoput voltage never goes below
0VDC. So it's only a small capacitor, a few pFs. If the other
capacitor is only a few pFs, then the diode capacitance would be
significant, and would vary depending on the DC voltage. This kind of
circuit is often used for AFC or voltage variable tuning in a receiver.

If the capacitor is hundreds or more pFs, then the diode is more likely
used for reverse voltage protection. Just in case someone puts the
battery in backwards.