parametric equalizer on an audio-mixer-sized PCB

Here's PLL FM transmitter circuit from china. This circuit uses the familiar 2SC1971 for final power amplifier stage. The PLL controller of the FM transmitter use SAA1057 and PIC16F628 (download HEX file). More: If want to change the active...

This is the diagram of the Electro-Harmonix graphic equalizer. The number of channels can be specified according to requirements by paralleling the components: C1, C2, R1, an operational amplifier, potentiometer, and a 470-ohm resistor. The frequency to be boosted...

This discussion continues from the audio tone control topic, which introduced both passive and active tone controls. The follow-up topics may include a 2-Band Active Tone Control or a 3-Band Active Tone Control. An audio equalizer is utilized to...

Designing a controller PCB for a 10x10 white LED matrix clock based on an ATmega328 AVR IC and a Maxim DS3234 SPI RTC. The challenge lies in controlling a custom non-standard 10x10 LED matrix. Initially, a Maxim MAX7219/7221 IC...

The circuit diagram presented is a triac-diac electronic fan regulator designed to reduce power consumption of electric fans, even at low speeds. Traditional resistor-inductor fan regulators tend to generate excess heat, wasting energy when the fan operates at lower...

Telephones are declining globally; however, India has over 350 million mobile phone users, alongside a significant number of traditional telephone users. This telephone timer is designed to save costs by controlling unnecessary time spent during phone calls. This simple...