Black Light Project

This is a simple ultra-violate light circuit diagram that can be powered by a 6 volt battery or power supply that is capable of supplying 1 or more amps.

Parts Total Qty. Description
C1 1 0.0047uf Mono Capacitor
C2 1 0.1uf Disc Capacitor
D1, D2 2 1N4007 Diode
FTB 1 Filtered Blacklight Tube
IC1 1 555 Timer IC
P1 1 10k Trim Pot
Q1 1 TIP30 PNP Power Transistor
R1 1 470 Ohm Resistor
R2 1 270 Ohm Resistor
T1 1 Medium Yellow Inverter Transformer
MISC 1 IC Socket, Heat Sink For Q1, Screw, Nut, Wire and PC Board

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Adjustable or Controllable Strobe Light

This is uses a much more powerful "Horse Shoe" Xenon tube. Which produces more light flash. You can control the flash rate up to about 20Hz. Do not look directly at the flash tube when this is running!

Parts:

R1 250 Ohm 10 Watt Resistor
R2 500K Pot
R3 680K 1/4 Watt Resistor
D1,D2 1N4004 Silicon Diode
C1, C2 22 uF 350V Capacitor
C3 0.47uF 400 Volt Mylar Capacitor
T1 4KV Trigger Transformer (see "Notes")
L1 Flash Tube (see "Notes")
L2 Neon Bulb
Q1 106 SCR
F1 115V 1A Fuse
Misc Case, Wire, Line Cord, Knob For R2


Note:

T1 and L1 are available from The Electronics Goldmine. This ciruits is NOT isolated from ground. Use caution when operating without a case. A case is required for normal operation. Do not touch any part of the circuit with the case open or not installed. Most any diodes rated at greater then 250 volts at 1 amp can be used instead of the 1N4004's. Do not operate this circuit at high flash rates for more than about 30 seconds or else C1 and C2 will overheat and explode. There is no on/off switch in the schematic, but you can of course add one.
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CHRISTMAS STAR By MAINS-OPERATED

There is a low cost circuit diagram of Christmas star that can be easily maked even by a novice. The main advantage of this circuit is that it does not equire any step-down transformer or ICs.

Parts List:
R1 ------------------ 100 ohm
R2 ------------------ 100 ohm
R3 ------------------ 10 ohm
R4 ------------------ 100K
R5 ------------------ 100K
R6 ------------------ 10K
R7 ------------------ 10K
C1 ------------------ 0.1µ
C2 ------------------ 220µ
C3 ------------------ 0.1µ
C4 ------------------ 47µ
C5 ------------------ 47µ
D1 ------------------ 1N4007
D2 ------------------ 1N4007
D3 ------------------ 1N4007
ZD1 ---------------- 5.6V
LED1 -------------- Any
T1 ------------------- BC548
T2 ------------------- BC548
T3 ------------------- BC548
MT1,MT2 --------- BT136

Circuit Design By: PRINCE PHILLIPS


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Telephone call Voice Changer Circuit

If your ask is that ...
How to make a telephone call voice changer circuit ?
 2) How to make a phone call voice changer circuit?
 3)How to convert male voice to female voice ?
This is a simple telephone call voice changer circuit . You can change male voice to famale voice by using this circuit diagram.

Parts :

P1______________10K Log. Potentiometer

R1,R10__________10K 1/4W Resistors
R2_______________1K 1/4W Resistor
R3______________50K 1/2W Trimmer Cermet or Carbon
R4,R6,R7,R14___100K 1/4W Resistors
R5______________47K 1/4W Resistor
R8______________68K 1/4W Resistor
R9_______________2K2 1/2W Trimmer Cermet or Carbon
R11_____________33K 1/4W Resistor
R12_____________18K 1/4W Resistor
R13_____________15K 1/4W Resistor
IC1___________LM358 Low Power Dual Op-amp
IC2_________TDA7052 Audio power amplifier IC

MIC1__________Miniature electret microphone

SPKR______________8 Ohm Small Loudspeaker

SW1____________DPDT Toggle or Slide Switch
SW2,SW3________SPST Toggle or Slide Switches


C1,C2,C3,C8,C9_100nF 63V Polyester Capacitors
C4______________10µF 25V Electrolytic Capacitor
C5_____________220nF 63V Polyester Capacitor (Optional, see Notes)
C6_______________4n7 63V Polyester Capacitor
C7______________10nF 63V Polyester Capacitor
C10____________220µF 25V Electrolytic Capacitor


J1____________6.3mm or 3mm Mono Jack socket

B1_______________9V PP3 Battery (See Notes)

Clip for PP3 Battery

This design fulfills these requirements by means of a variable gain microphone preamplifier built around IC1A, a variable steep Wien-bridge pass-band filter centered at about 1KHz provided by IC1B and an audio amplifier chip (IC2) driving the loudspeaker.

Notes:

1) The pass-band filter can be bypassed by means of SW1A and B: in this case, a non-manipulated microphone signal will be directly available at the line or loudspeaker outputs after some amplification through IC1A.

2) R3 sets the gain of the microphone preamp. Besides setting the microphone gain, this control can be of some utility in adding some amount of distortion to the signal, thus allowing a more realistic imitation of a telephone call voice.

3) R9 is the steep control of the pass-band filter. It should be used with care, in order to avoid excessive ringing when filter steepness is approaching maximum value.

4) P1 is the volume control and SW2 will switch off amplifier and loudspeaker if desired.

5) C5 is optional: it will produce a further band reduction. Some people think the resulting effect is more realistic if this capacitor is added.

6) If the use of an external, moving-coil microphone is required, R1 must be omitted, thus fitting a suitable input jack.

7) This circuit was intended to be powered by a 9V PP3 battery, but any dc power supply in the 6 - 12V range can be used successfully.

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Telephone Sharer circuit 9 channel

Introduction:

This circuit is able to handle nine independent telephones (using a single telephone line pair) located at nine different locations, say, up to a distance of 100m from each other, for receiving and making outgoing calls, while maintaining conversation secrecy. This circuit is useful when a single telephone line is to be shared by more members residing in different rooms/apartments.
Description:

Normally, if one connects nine phones in parallel, ring signals are heard in all the nine telephones (it is also possible that the phones will not work due to higher load), and out of nine persons eight will find that the call is not for them. Further, one can over- hear others’ conversation, which is not desirable. To overcome these problems, the circuit given here proves beneficial, as the ring is heard only in the desired extension, say, extension number ‘1’.

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For making use of this facility, the calling subscriber is required to initially dial the normal phone number of the called subscriber. When the call is established, no ring-back tone is heard by the calling party. The calling subscriber has then to press the asterik (*) button on the telephone to activate the tone mode (if the phone normally works in dial mode) and dial extension number, say, ‘1’, within 10 seconds. (In case the calling subscriber fails to dial the required extension number within 10 seconds, the line will be disconnected automatically.) Also, if the dialed extension phone is not lifted within 10 seconds, the ring-back tone will cease.

Operation:

The ring signal on the main phone line is detected by opto-coupler MCT- 2E (IC1), which in turn activates the 10-second ‘on timer’, formed by IC2 (555), and energises relay RL10 (6V, 100- ohm, 2 C/O). One of the ‘N/O’ contacts of the relay has been used to connect +6V rail to the processing circuitry and the other has been used to provide 220-ohm loop resistance to de-energise the ringer relay in telephone exchange, to cut off the ring.



When the caller dials the extension number (say, ‘1’) in tone mode, tone receiver CM8870 (IC3) outputs code ‘0001’, which is fed to the 4- bit BCD-to-10 line decimal de- coder IC4 (CD4028). The output of IC4 at its output pin 14 (Q1) goes high and switches on the SCR (TH-1) and associated relay RL1. Relay RL1, in turn, connects, via its N/O contacts, the 50Hz extension ring signal, derived from the 230V AC mains, to the line of telephone ‘1’. This ring signal is available to telephone ‘1’ only, because half of the signal is blocked by diode D1 and DIAC1 (which do not conduct below 35 volts).

As soon as phone ‘1’ is lifted, the ring current in- creases and voltage drop across R28 (220-ohm, 1/2W resistor) increases and operates opto-coupler IC5 (MCT-2E). This in turn resets timer IC2 causing:



(a) interruption of the power supply for processing circuitry as well as the ring.

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A small FM transmitter

This FM transmitter has an operating frequency of about 80 to 115MHz. Under reasonable circumstances you will be able to receive its signal at a distance of about 200 meters. Although it is low-power, it might be illegal in your part of the planet.

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Make a TV Transmitter

One of the most useful gadgets a video enthusiast can have is a low-power TV Transmitter. Such a device can transmit a signal from a VCR to any TV in a home or backyard. Imagine the convenience of being able to sit by the pool watching your favorite movie on a portable with a tape or laserdisc playing indoors. You could even retransmit cable TV for your own private viewing. Videotapes can be dubbed from one VCR to another without a cable connecting the two machines together.

When connected to a video camera, a TV transmitter can be used in surveillance for monitoring a particular location. The main problem a video enthusiast has in obtaining a TV transmitter is that a commercial units are expensive. However, we have some good news! You can build the TV Transmitter described here for less than $30 in one evening! The easiest way to do that is to order the kit that‚s available from the source given in the Parts List (a custom case for the kit is also available). Nevertheless, we present enough information here to build the TV Transmitter from scratch.
The TV Transmitter combines line- level audio and video signals, and transmits the resulting signal up to 300 feet. The circuit can be powered from a 9- volt battery. It is suggested that a 12-volt DC supply during be used during the alignment procedure. This would insure maximum transmission range and best possible picture. Aligning the TV Transmitter requires no special equipment whatsoever, and it is a very simple procedure. The Transmitter's output can be tuned to be received on any TV channel from 2 to 6. The range of channels is wide enough so that the unit will not interfere with other TV viewers who are nearby. To comply with FCC rules, it is mandatory the nearby TV viewers are not disturbed by the transmission. If your activities interfere with the reception from a licensed station, regardless of the reason, you must shut down your unit.

Circuit Description:

Figure 1 is the schematic diagram of the TV Transmitter circuit. Video signals input at jack J1 are first terminated by resistor R6 and coupled through capacitor C1 to clamping-diode D1. The clamping forces the sync pulses to a fixed DC level to reduce blooming effects. Potentiometer R3 is used to set the gain of the video signal; its effect is similar to that of the contrast control on a TV set. Bias-control R7 can be used to adjust the black level of the picture so that some level of signal is transmitted, even for a totally dark picture. That way, a TV receiver can maintain proper sync. As we'll get to later, potentiometers R3 and R7 are cross adjusted for the best all-around performance.

RF-transformer T1 and its internal capacitor form the tank circuit of a Hartley oscillator that's tuned to 4.5 megahertz. Audio signals input at J2 are coupled to the base of Q3 via C2 and R4: the audio signal modulates the base signal of Q3 to form an audio subcarrier that‚s 4.5-megahertz higher than the video-carrier frequency. The FM modulated subcarrier is applied to the modulator section through C5 and R9. Resistor R9 adjusts the level of the subcarrier with respect to the video signal. Transistors Q1 and Q2 amplitude modulate the video and audio signals onto an RF-carrier signal. The operating frequency is set by coil L4, which is 3.5 turns of 24- gauge enameled wire on a form containing a standard ferrite slug.

That coil is part of a Colpitts tank circuit also containing C7 and C9. The tank circuit forms Q4's feedback network, so Q4 oscillates at the set frequency The RF output from the oscillator section is amplified by Q5 and Q6, whose supply voltage comes from the modulator section. Antenna matching and low-pass filtering is performed by C12, C13, and L1. Resistor R12 is optional; it is added to help match the output signal to any kind of antenna. (More on that in a moment.)

 PARTS LIST FOR THE
TV TRANSMITTER

SEMICONDUCTORS

D1—1N914 silicon diode
Q1-Q—2N3904 NPN transistor
RESISTORS
(All fixed resistors are 1/4-watt, 5% units .)
R1, R2, R11—1000-ohm
R3, R7—1000-ohm trimmer potentiometer, PC-
mount
R4, R9, R10—10,000-ohm
R5—47,000-ohm
R6—75-ohm
R8—4700-ohm
R12—75-ohm (optional, see text)

CAPACITORS

C1, C8—100-µF, 16-WVDC, electrolytic
C2—2.2--µF, 50-WVDC, electrolytic
C3-C6, C11, C14, C15—001-µF, ceramic-disc
C7, C9—2.2-pF, ceramic-disc
C10—100-pF, ceramic-disc
C12, C13—68-pF, ceramic-disc

ADDITIONAL PARTS AND MATERIALS

ANT1—Antenna, telescopic-whip
B1—9-volt battery
J1-J3—RCA jack, PC-mount
L1—0.15-µH miniature inductor
L2, L3—2.2-µH miniature inductor
L4—0.14- to 0.24-mH adjustable, slug-tuned coil
(see text)
S1—SPST, push-button switch, normally open
T1—4.5-MHz 1F-can-style RF  transformer (see
text)
Printed-circuit materials or pre-fab PC board,
battery holder and connector, pair of RCA
patch cords, solder, hardware, etc.
Note: The following items are available from
     Ramsey Electronics, Inc.
     793 Canning Parkway
     Victor, NY  14564
     Tel. 716-924-4560
TV-6 TV Transmitter Kit (includes PC board and all
components except R12)—$27.95; kit of all
components (except R12)—$17.95; PC board
only—$10.00; CTV matching-case set—$14.95.
NY State residents please add appropriate sales
tax.

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TV-Transmitter

A VHF band TV transmitter using negative sound modulation and PAL video modulation. This is suitable for countries using TV systems B and G.

Notes: The frequency of the transmitter lies within VHF and VLF range on the TV channel, however this circuit has not been tested at UHF frequencies. The modulated sound signal contains 5.5 -6MHz by tuning C5. Sound modulation is FM and is compatible with UK System I sound. The transmitter however is working at VHF frequencies between 54 and 216MHz and therefore compatible only with countries using Pal System B and Pal System G.

For more information on TV systems visit the links below:

Television Frequency Table
Televison system frequency and channel standards.

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Make a FM Booster

There is a low-cost circuit of an FM booster which can be used to listen programmes from high distant FM stations clearly.
The circuit comprises a common-emitter tuned RF preamplifier wired around VHF or UHF transistor 2SC2570. (Only C2570 is annotated on the transistor body.)

Parts List:
R1 ---------------------------------- 27K
R2 ---------------------------------- 270K
R3 ---------------------------------- 1K
C1 ---------------------------------- 5.6p
C2 ---------------------------------- 5.6p
C3 ---------------------------------- 1n
C4 ---------------------------------- 10p
C5 ---------------------------------- 10p
C6 ---------------------------------- 0.1micro
VC1 -------------------------------- 22p
VC2 -------------------------------- 22p
T1 ----------------------------------- C2570
L1 ----------------------------------- 20SWG ( 4 Turns ; 5mm diameter)
L2 ----------------------------------- 20SWG ( 3 turns ; 5mm diameter)

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Medium Power FM Transmitter

This is a Medium Power FM Transmitter. The range of this FM transmitter is around 80-100 metres at 9V-12V DC supply.

The circuit comprises three stages. The first stage is a microphone preamplifier built around BC548 transistor. The next stage is a VHF oscillator wired around another BC548. (BC series transistors are generally used in low-frequency stages. But these also work fine in RF stages as oscillator.) The third stage is a class-A tuned amplifier that boosts signals from the oscillator. Use of the additional RF amplifier increases the range of the transmitter.



Circuit Designed by PRADEEP G.

For more information Just Click Hare

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