Hi all,
I just got interested in electrinics few days ago. Trying to focus on simple analog audio circuits for now and done quite alot of reading on this subject, but there are still a few questions that bugs me..
As an exaple lets take this tone control circuit (attached).
1. How do I count current I should use for the circuit? (If I had one resistor in circuit, I would use I = V / R, I gues but what if I had one capacitor, diode or transistor or when it gets comlex like in pic ?)
2. How do I count max safe input? Is that linked somehow to "input inpendance" (take a look at notes at the end of the post)?
3. What is a "buffer" (notes)? I find this in almost all audio circuits, but can't find info about it. ;(
Thanks very much and sorry for noobyness, it's just I can't find this info anywhere and thought you guys could help a little
Notes for the circuit:
"The first BC109C transistor (left hand side) is acting as a buffer. It provides the circuit with a high input impedance, around 250k has a voltage gain of slightly less than unity. As the Baxendall tone control circuit is a passive design, all audio frequencies are attenuated. The position of the controls and reactance of the capacitors alters the audio response. The last transistor provides a slight boost of about 3x. The output is designed to feed an amplifier with input impedance of 10k to 250k. Both tone controls should be linear type potentiometers."
Circuit and notes taken from: **broken link removed**
I just got interested in electrinics few days ago. Trying to focus on simple analog audio circuits for now and done quite alot of reading on this subject, but there are still a few questions that bugs me..
As an exaple lets take this tone control circuit (attached).
1. How do I count current I should use for the circuit? (If I had one resistor in circuit, I would use I = V / R, I gues but what if I had one capacitor, diode or transistor or when it gets comlex like in pic ?)
2. How do I count max safe input? Is that linked somehow to "input inpendance" (take a look at notes at the end of the post)?
3. What is a "buffer" (notes)? I find this in almost all audio circuits, but can't find info about it. ;(
Thanks very much and sorry for noobyness, it's just I can't find this info anywhere and thought you guys could help a little
Notes for the circuit:
"The first BC109C transistor (left hand side) is acting as a buffer. It provides the circuit with a high input impedance, around 250k has a voltage gain of slightly less than unity. As the Baxendall tone control circuit is a passive design, all audio frequencies are attenuated. The position of the controls and reactance of the capacitors alters the audio response. The last transistor provides a slight boost of about 3x. The output is designed to feed an amplifier with input impedance of 10k to 250k. Both tone controls should be linear type potentiometers."
Circuit and notes taken from: **broken link removed**