[SOLVED] Types of Circuit Relays I Can Use

[~analoger~]

Hello,

This is my first post here.

I'm trying to design a circuit that has a capacitance/resistance controlled oscillator. I want to add a frequency option control panel from which a frequency is selected using push buttons like the ones used in a calculator. By design the circuit will not use a variable capacitor/resistor, I will hard-wire a fixed array of both Cs and Rs.

First question, to connect a specific C or R to obtain the desired frequency the electro-mechanical relay is not an option, so here I'm probably looking for semiconductor switching devices. However as I'm reading about transistors they let current flow so they are not really isolated from the main circuit, like traditional relays. Is there any other equivalent to mechanical relays?

Second question, what circuit element should I use for push-buttons, like the ones in a calculator?
So when the switch is released it turns on/off something and state is preserved until another trigger takes place.

Help appreciated.

 

[BradtheRad]

The 4066 IC (quad bilateral switch) might be useful in such a project.
It switches analog signals with no moving parts.
Its 'On' resistance is low.
It may or may not be compatible with an oscillating circuit. Or it may prefer for the oscillations to be in the positive polarity range.

 

[~analoger~]

Sounds a good idea. However I've found that there's something called semiconductor relay that uses opto-Triac for switching, or actually in my case, connecting. I will have to further research both options.

 

[chuckey]

I would configure the oscillator to use fixed Cs and switched Rs. This is because virtually all semiconductor switches will have a small series resistance when "on" which will effect the phase shift of capacitors while will just add an additional resistance to a resistor.
Frank