500 Watt Audio Power Amplifier

What can be done to increase available audio power amplifier? The answer is either decrease load impedance or increase supply voltage. The lower the impedance, the more current is needed, making the construction of low impedance output stages more difficult (there are some other practical limits), so lets increase supply voltage!

Components/parts list :
R1,R11
47K
R2,R3 33K
R4 1K5
R5,R7 2K2
R6,R8 100R
R9,R10 56R
R12 820R
R13 10R/5W

C1 220nF
C2,C3,C4 100uF/100V
C5,C6 100pF
C7 100nF/100V

D1,D2 IN4002

TR1,TR2 D438
TR3,TR4 B560
TR5,TR8 A958
TR6,TR7 C2168
TR9,TR10 C2922
TR11,TR12 A1216

Read More

Explanation Fuse Box Chevrolet S10 1998 Diagram

Fuse Box Chevrolet S10 1998 Diagram - This show you about Fuse Box Chevrolet S10 1998 Diagram.

Fuse Box Chevrolet S10 1998 Diagram

Fuse Panel Layout Diagram Parts: headlamp grounding relay, blower motor relay, multifunction switch, stop lamp switch, transfer case shift control module, park and turn signal lamp, electronic brake control module, ignition switch, starter relay, ignition switch, park n turn signal lamp, headlamp switch, auxiliary power, radio battery, cigar lighter, courtesy lamp, power locks, park lamp relay. Read More

Negative Output Switching Regulator

There are only a limited number of switching regulators designed to generate negative output voltages. In many cases, it’s thus necessary to use a switching regulator that was actually designed for a positive voltage in a modified circuit configuration that makes it suitable for generating a negative output voltage. The circuit shown in Figure 1 uses the familiar LM2575 step-down regulator from National Semiconductor (www.national.com). This circuit converts a positive-voltage step-down regulator into a negative-voltage step-up regulator. It converts an input voltage between –5 V and –12 V into a regulated –12-V output voltage.

Note that the output capacitor must be larger than in the standard circuit for a positive output voltage. The switched current through the storage choke is also somewhat higher. Some examples of suitable storage chokes for this circuit are the PE-53113 from Pulse (www.pulseeng.com) and the DO3308P-153 from Coilcraft (www.coilcraft.com). The LM2575-xx is available in versions for output voltages of 3.3V, 5 V, 12 V and 15 V, so various negative output voltages are also possible. However, you must pay attention to the input voltage of the regulator circuit. If the input voltage is more negative than –12 V (i.e., Vin <–12 v), the output voltage will not be regulated and will be lower than the desired –12 v.


The LM2575 IC will not be damaged by such operating conditions as long as its maximum rated input voltage of 40 V is not exceeded. High voltage (HV) types that can withstand up to 60 V are also available. Although the standard LM2575 application circuit includes circuit limiting, in this circuit the output current flows via the diode and choke if the output is shorted, so the circuit is not short-circuit proof. This can be remedied by using a Multifuse (PTC) or a normal fuse. There is also an adjustable version of the regulator with the type designation LM2575-ADJ (Figure 2). This version lacks the internal voltage divider of the fixed-voltage versions, so an external voltage divider must be connected to the feedback (FB) pin. The voltage divider must be dimensioned to produce a voltage of 1.23 V at the FB pin with the desired output voltage. The formula for calculating the output voltage is:

Vout = 1.23 V × (1 + [R1 ÷ R2])

The electrolytic capacitors at the input and output must be rated for the voltages present at these locations.
Read More

3 4 W power amplifier schematic

The schematic above is amplifier based on ic TA7211P or TA7212P , circuit above using OT transformer as a booster amplifier again. The amplifier suitable used on outside / field, because by using a transformer OT is identical to the PA amplifier.

Part List :

R  = 1K , 10R , 3K3

C  = 1uF , 10uF , 1n , 68u, 3u3, 2n2 x 2, 100u 

IC = TA 7211P / TA7212P

Technical information :

Max Vcc = 15 VDC

Min Vcc  = 4 VDC

Po            = 3,4 W

Rl            = 8 Ohm

Icco         = 16 mA

Read More

NE602 Voice Scrambler Descrambler

This circuit uses an NE602 as an inversion mixer. U2 is set to run at about 2.5 to 3.5 kHz. U3 drives a loudspe

Read More

General Purpose NiCd Battery Charger

There is a wide variety of NiCd (nickel-cadmium) battery chargers on the market, but there are not many that can work from an in car 12 V cigar lighter. Such a charger would, for instance, be of interest to campers and caravanners who do not have a 230 V a.c. mains supply available. To satisfy the needs of these users, a charger could be designed for operation from the cigar lighter, but it is, of course, of far greater interest if it could also work from the domestic mains supply. Furthermore, it would also be very useful if a number of cells, say, 1 to 4, of different format could be charged simultaneously.

Lastly, another benefit would be if the charger would automatically switch off once the battery or cells have been charged fully. The charger described in this article does all that: it accommodates batteries or cells Type R6 and R14. Switching off after a period of 2 h 30 m, 5 h, or 10 h is arranged by 3-way switch S1. The 2 h 30 m period is for charging Type R6 batteries (1/2 charge), the 5 h period for fully charging Type R6 batteries or half charging Type R14 batteries, and the 10 h period for fully charging Type R14 batteries. Light-emitting diode D1 lights when charging is taking place. Charging after the set period has elapsed can be continued, if so desired, only by switching the supply off and then on again.

The time periods are determined by counters IC1 and IC2, Type 4060 and 4020 respectively. The 4060 has an integral oscillator, whose frequency is set to 932 Hz with preset P1 and the aid of a frequency meter. For various reasons, such as the values of the components used and parasitic elements, the oscillator itself operates at a slightly higher frequency – of the order of 1 kHz. The frequency of the signal at the wiper of P1 is divided by 214, so that the frequency of the signal at Q13 of IC1 is 0.056 Hz, equivalent to a pulse every 17.6 s. The signal at Q13 is applied to the input, pin 10, of IC2. When switch S1 is in position 2 h 5 m (output Q10 of IC2), the divisor should be 210 (1024).

However, contrary to what these figures indicate, the time period stops at half that at output Q10. To obtain a charging period of 2 h 30 m, that is, 9,000 seconds, which should correspond to half a period at output Q9 of IC2, the oscillator period must be 9000×2/16.7×106=1.073 ms, which corresponds to a frequency of 932 Hz as mentioned earlier. On power-on, only counter IC2 is reset, since an error of a few seconds that may arise in IC1 is of no significance. This arrangement simplifies the design. When the time set has elapsed, that is, charging is finished, diode D1 goes out.

The charging current is fixed by darlington transistor T3, which is a classical design of a current source with negative feedback. The transistor tends to hold its emitter potential at 1.3 V, but this requires the aid of a zener diode, D2. In this type of design, the thermal stability is, in fact, totally acceptable, because the temperature of the zener diode, in view of the small current this draws and its consequent low temperature rise, hardly affects the charging current Transistor T1 is either on or off and serves to power the on/off indicator LED. It is needed to prevent an overload on the output of counter IC1 if this would be required to absorb the total current (about 7mA) drawn by the diode.

Transistor T2 discontinues the charging when the time set by S1 has elapsed by earthing the base of darlington T3. Diodes D3–D14 are connected in threesomes across the terminals of the batteries to be charged: D3–D5 across those of battery Bt1, D6–D8 across those of Bt2, and so on. Diode D15 prevents the batteries to be charged from being discharged when the supply fails. When the charger is used in a vehicle, additional precautions should be taken to ensure that any spurious surges on the vehicle power lines do not adversely affect the charger’ s operation. The battery holder should be one that can accommodate four size R6 (AM3; MN1500; SP/HP7; mignon) or R14 AM2; MN1400; SP/HP11; baby) batteries.

The length of these batteries, but not their diameter, is the same (about 45 mm). When the charger is used at home, it may be powered via a suitable 15V mains adaptor. It draws a current of about 150mA. A final word of warning: it is possible for batteries to be connected to the charger with incorrect polarity. This may result in a very large discharge current and even destruction of the battery. It is, therefore, imperative to verify the correct polarity of the battery before inserting it into the holder.
Read More

Fuse Box Toyota 1996 Corolla Engine Compartment Diagram

Fuse Box Toyota 1996 Corolla Engine Compartment Diagram - Here are new post for Fuse Box Toyota 1996 Corolla Engine Compartment Diagram.

Fuse Box Toyota 1996 Corolla Engine Compartment Diagram

Fuse Panel Layout Diagram Parts: emergency flasher, horns, multiport file injection, spare fuse, headlight, charging system, fuel injection system, power window, power door lock system, air conditioning, starting system, electric cooling fan, air conditioning system, tail light, anti lock brake system. Read More