The NE58633 is a noise reduction stereo Class D Bridge-Tied Load (BTL) helmet driver amplifier. Each channel has a Class D driver's helmet BTL amplifier, a electret microphone preamplifier for low noise, noise reduction circuit and returned to the music amplifier input.
NE58633 is the battery voltage from 0.9 V to 1.7 V, the chip employs on-chip DC-DC boost converter and the internal reference voltage Vref which is filtered and country of origin of noise removal. It is a mute control, and plop, and then click a reduction circuit. The amplifier gain of the microphone and amplifier of the filter is fixed with external resistors. Differential architecture provides better noise immunity.
The NE58633 is able to drive through a 800 mVrms 16 Ω or 32 Ω load and offers Electrostatic discharge (ESD) protection and short circuit. Available in 32-pin HVQFN32 (5 mm x 5 mm x 0.85 mm) package for high density of small and layout is ideal for noise-reduction headsets and audio teaching aids.
Caracteristic of NE58633
- Low current consumption of 4.4 mA
- 0.9 V to 1.7 V battery operating voltage range
- 1 % THD+N at VO = 1 VM driving 16 Ω with a battery voltage of 1.5 V
- 10 % THD+N at 800 mVrms output voltage driving 16 Ω and 32 Ω loads with a battery voltage of 1.5 V
- Output noise voltage with noise reduction circuit typically 31 mVrms for Gv(cl) = 25 dB
- On-chip mute function
- Plop and click reduction circuitry
- Class-D BTL differential output configuration
- Electret microphone noise reduction polarization amplifier with external gain adjustment using resistors
- Music and filter amplifier with external gain adjustment using resistors
- DC-to-DC converter circuitry (3 V output) with 2.5 mA (typical) load current
- Internal voltage reference pinned out for noise decoupling
The preamplifier is designed for use with dynamic (moving coil TM) microphone with an impedance of 200 Ω balanced and terminals. It's a pretty simple design, which can also be seen as an amplification stage based on a single instrument type NE5534 op amps. To get the most common mode rejection (CMR) in a balanced signal, the reasons for the division of the dividers (R1-R4-R5 and R2, respectively) to the inputs of operational amplifier must be identical. Since this can be difficult to achieve in practice, a preset potentiometer P1 is connected in series with R5. The preset allows the common mode rejection optimal.
The capacitor C1 prevents input voltage while the resistor R7 ensures the stability of the amplifier with capacitive loads.
Resistor R3 prevents the amplifier goes into oscillation when the input has been interrupted. If the microphone cable is reasonably long, R3 is not necessary, because the parasitic capacitance of the cable to ensure the stability of the amplifier. It should be noted, however, that because the R3 improve the> 70 dB CMR> 80 dB. Performance of the preamplifier is very good. THD + N (total harmonic distortion plus noise) is less than 0.1%, where the input signal is 1 mV and the impedance of 50 Ω current. Under the same conditions, the signal to noise ratio is -62.5 dB. When the values of the components have been defined, the gain is 50 dB ('316). After careful adjustment P1 at 1 kHz, CMR, without R3, is 120 dB. The supply voltage is ± 15 V. The power amplifier pulls the voltage of about 5.5 mA. Note: the removal of power lines with L1, L2, C2-C5.
Here is a simple lie detector that can be built in minutes, but can be incredibly useful when you want to know if someone is really telling you the truth. It is not as sophisticated as those that the pros use, but it works. It works by measuring skin resistance, which goes down when you are lying.
R133K 1/4W Resistor
R31.5K 1/4W Resistor
C11uF 16V Electrolytic Capacitor
Q12N3565 NPN Transistor
M10-1 mA Analog Meter
MISC1Case, Wire, Electrodes (See Nots)
- The electrodes can be alligator clips (although they can be painful), electrodes (like the kind they use in hospital), or just the son and bands.
- You can use the circuit, connect the electrodes to the back of the hand subjects, approximately 1 cm intervals. Then adjust the meter reading 0 Applications. He knows the subject is lying when the meter changes.
The series is I do here is a series regulator Volume, Bass and Balance digital Trable (tone control). The core of this circuit is an output-type IC manufacturer Maxim MAX5406, while the IC is an audio processor that comes with the switch successfully interface for tone control setup above. The circuit diagram is as follows
The above scheme uses support components and this makes very little can be done with only a small matchbox, even if used all SMD components can be reduced in size to half that time I'll just give Simply design, following pic:
In this circuit, intercom, an 8-ohm is used for both the microphone and output device. Phase BC109C extends a common base mode, in which case a good voltage gain, while providing a low input impedance of the speaker. Self-DC bias is used allowing increases of transistors in progress. LM386 is used in inverting mode amplifier power to increase the voltage gain and drives 8 ohm. 10k potentiometer volume control works, and the overall benefit can be adjusted using the 5k in advance. Double-pole switch, turn the position of the speakers, so you tend to speak and another to hear. Manually operate the switch (from inside the house) allows two-way communication.