6N2P Tube Pre Tone Low Volt Low Cost Circuit

That if one wants to create a high fire. Put values ​​as I get it offline … because I reference values ​​from the Data Sheet.

But do not suggest we fire up to 250 Volts Capacitor find the 350v. The price is expensive and over again.
I recommend creating a 230v. And then use the Cap 250 v. easy to find cheap used instead of the sound was no difference between voltage 250 to 230. 

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0 30 Volt Power Supply

linear power supply, shown in the schematic, provides 0-30 volts, at one amp, maximum, using a discrete transistor regulator with op amp feedback to control the output voltage. The supply was constructed in 1975-6 & has a constant current mode that is used to recharge batteries.

With reference to the schematic, lamp, LP2, is a power on indicator. The other lamp (lower) lights when the unit reaches its preset current limit. R5, C2, & Q10 (TO-3 case) operate as a capacitor multiplier. The 36 volt zen-er across C2 limits the maximum supply voltage to the op amps supply pins. D5, C4, C5, R15, & R16 provide a tiny amount of negative supply for the op amps so that the op amps can operate down to zero volts at the output pins (pins 6). A more modern design might eliminate these four parts & use a CMOS rail-to-rail op-amp. Current limit is set by R3, D1, R4, R6, Q12, R10, & R13 providing a bias to U2 that partially turns off transistors Q9 & Q11 when the current limit is reached. R4 is a front panel potentiometer that sets the current limit, R22 is a front panel potentiometer that sets the output voltage (0-30 volts), & R11 is an internal trim-pot for calibration. The meter is a one milliamp meter with an internal resistance of 40 ohms. Switch S1 determines whether the meter reads 0-30 volts, or 0-1 amp.

A more new circuit might use a single IC regulator, such as the MC78XX, or MC79XX series, immediately after the half wave rectifier, to replace about 30 parts, or at least a high precision zen-er diode to replace D10 as the voltage reference. The LM4040 is such voltage reference & has excellent stability over temperature. IC regulators such as the MC78XX series may finally become obsolete as newer IC regulators are designed, however, discrete transistors, op-amps, & zeners are more generic, have an extended production lifespan, & permit the designer to demonstrate that they understands the principles of linear regulated power supply operation.

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6 12 Volt audio amplifier

The above is an amplifier circuit using supply voltages from 6 volts DC to 12 Volt DC. Power output of the amplifier is quite low with only 1 Watt 8 ohm impedance. You can apply this to the audio signal amplifiers that require strengthening are not so large as in the pocket radio.

Part List :
R1 =  100K
R2 = 39R
R3 = 100R
C1 = 100nF
C2 = 100uF
C3 = 100uF
C4 = 100uF
C5 = 470uF
C6 = 100nF
C7 = 68pF
C8 = 1nF
C9 = 47uF
IC = SFC2790C

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LED Volt Meter Circuit

Here is a Simple LED Volt meter to Monitor the charge level in Lead Acid Battery or Tubular battery. The terminal voltage of the battery is indicated through a four level LED indicators. The nominal terminal voltage of a Lead Acid battery is 13.8 volts and that of a Tubular battery is 14.8 volts when fully charged. The LED voltmeter uses four Zener diodes to light the LEDs at the precise breakdown voltage of the Zener diodes. Usually the Zener diode requires 1.6 volts in excess than its prescribed value to reach the breakdown threshold level. When the battery holds 13.6 volts or more, all the Zener breakdown and all LEDs light up. When the battery is discharged below 10.6 volts, all the LEDs remain dark. So depending on the terminal voltage of the battery, LEDs light up one by one or turns off.
Circuit diagram:

 LED Volt Meter Circuit Diagram

 

 

http://streampowers.blogspot.com/2012/06/led-volt-meter-circuit.html 

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9 20 Volt amplifier circuit

For this time I will post the scheme following an amplifier of the IC KA2203, SN16975, TBA820, UL1482P. Which has 4 Watt power output with 4 Ohm impedance. At least 8 Volt supply voltage and a maximum of 20 volts.

Part List

R1 = 100K

R2 = 56R 

R3 = 56R

Use 1/2 W resistor

C1 = 47uF

C2 = 100uF
C3 = 100uF
C4 = 470uF
C5 = 470pF
C6 = 0.22uF
C7 = 100uF
U1 = KA2203 , SN16975, TBA820, UL1482P

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