The function of this circuit is similar with the hum filter in our previous circuit, but it use transistors instead of op-amps. It uses BC109 transistors, but any low noise high gain type will be suitable. This hum filter is adjustable via trimmer pots to fine tune it’s notch depth. The figure below shows the schematic diagram of the circuit.
The power supply should be hum free, or the circuit itself will generate hum. The best way is to a battery, but a IC-regulated supply is adequate. [Circuit's schematic diagram source: elecfree.com]
Possibly Related Articles:
- Notch Filter: The Circuit’s Diagram and The Design Formula
Notch filter is known as band-cut filter or band-reject filter. The fuction of this filter is to remove some frequency portion of a signal. The schematic diagram of this filter... - Bulk Transistor Tester - An Easy Transistor Gain Classifier
This transistor tester is very helpful if you need to sort bulk transistors. In some market, if you know where to find it, sometimes you can get transistors sold in... - Second Order Butterworth Low-Pass Filter
A second order filters can be constructed using LC (inductor-capacitor) passive circuits, and they have been implemented for radio frequency for cheap and simplicity. For audio frequency range, unfortunately the... - Hum Filter, An Ultimate Weapon To Remove AC Line Noise
You might think that hum noise is produced by electronic device with improper design, yes you're right. And you might choose to solve the trouble maker, the source. You begin... - Butterworth Second Order High-Pass Filter: The Circuit and The Formula
For high pass filter, this circuit is similar to low-pass filter circuit, but the position for resistors and capacitor are interchanged. Here is the circuit's schematic and formula: Similar with...
| DESIGN BY 