Electronic – High Pass Filter configuration with diodes and electrolytic caps

diodeselectrolytic-capacitorhigh pass filter

I'm quite new to electronics and I'm trying to make a high pass filter to get rid of some DC component of a signal. For that, I thought of using a capacitor along with a resistor in the usual HPF configuration (values are generic):

schematic

simulate this circuit – Schematic created using CircuitLab

However, since my signal is positive and negative, as far as I understand I can't use an electrolytic capacitor since they are polarised. To make up for that, I thought of the following configuration (it is quite simple so if it works I guess it may be quite standard), but since I haven't designed many circuits I have no idea if it works or not:

schematic

simulate this circuit

Is this any good?
Thanks in advance!

Best Answer

A couple notes:

  • A high-pass filter removes or changes the DC level of a signal.
  • The polarity of the DC-blocking capacitor cares only about the DC level of both sides, not the alternating high-frequency signal.

So if you know whether the offset voltage will be positive or negative, you can use the simple circuit.

If the offset can vary higher or lower than the desired output offset, you can arrange two high-pass filter stages where you know the direction of each. For example, if the input offset can vary around 0V but never be more than +5V:

schematic

simulate this circuit – Schematic created using CircuitLab