An Accurate Reaction Timer Circuit

Add a cheap stopwatch to this circuit to produce an accurate reaction timer. The circuit is wired in parallel with the start/stop button in the watch via a 2.5mm socket, which fits snugly in one corner of the casing. The person conducting the test (the "tester") resets the stopwatch and turns on the reaction timer’s power switch (S3).

The person being tested (the "subject") places his or her fingers near the "STOP" push-button switch (S4). Next, the tester covertly sets a delay time with VR1 and selects either the LED or buzzer alarm via S2. To initiate the sequence, the tester then presses the "START" switch (S1). This triggers 555 timer IC1, which is wired as a monostable. Its output (pin 3) goes high for 2-12 seconds as determined by the setting of VR1. At the end of this delay pin 3 goes low and triggers IC2, another 555 timer in monostable mode.

Circuit diagram:

 An Accurate Reaction Timer Circuit Diagram

The output from IC2 (pin 3) activates the alarm (buzzer or LED) for about 0.5s. After inversion by Q1, it also triggers IC3, another 555 monostable. The positive pulse from IC3 turns on Q2, briefly closing the start/stop switch circuit in the watch. The watch starts to count up. After a short period, the subject reacts to the alarm and pushes the "STOP" button (S4), freezing the stopwatch. The reaction time can then be read off with 1/100th of a second accuracy.

Comparative reaction times could be measured when a subject is: rested or tired, silent or talking, before or after a night out, using a mobile phone, etc. For motoring realism, rig up dummy accelerator and brake pedals, with the brake switch making the stop contact. Or take it to your club and test people as they enter and after they’ve been "steadying their nerves" at the bar.

Author: A. J. Lowe - Copyright: Silicon Chip Electronics

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Telephone Ringer Circuit

If you are lucky enough to have a big house, a large garden, and small children, this project just might interest you. It’s actually a telephone ringer capable of making any mains-powered device work from the ringer of your fixed line. With it, you will be able to control a high-powered siren or horn, as you like, in order to relay and amplify the low-level sound of your telephone (making it audible in a big house or in a large garden)! Alternatively, you can make a lamp light (or an indicator light) and so create a ‘silent ringer’ (helpful when small children are napping).

The other interesting part of this simple and inexpensive project is that it doesn’t require a power supply, contrary to similar items on sales in the shops. Before examining the drawing and understanding the principle involved, it is important to know that the ringer voltage on a fixed telephone line is pretty high. Since Europe and the EU Commission have not yet interfered, the exact value of this voltage and its frequency varies according to the country, but that’s not important here. The line carries direct current whether unoccupied or occupied.

Moreover, no more than a few hundred mAs needs to be stolen from an unoccupied telephone line to make the PSTN exchange believe the line is occupied. Therefore, capacitor C1 has the dual role of insulating this project with respect to direct current present on the line while unoccupied, or while occupied, while also allowing the ringer current to pass. The latter is rectified by D1 and clipped by D2 which makes about 6 V DC available to the C2 terminals when a ringer signal is present.

Circuit Diagram :

 Telephone Ringer Circuit Diagram

This voltage lights LED D3 which only serves as a visual indicator of proper operation as does the LED contained in IC1. This is a high-power photo triac with zero crossing detection from the mains, which allows it to switch the load it controls without generating even the lowest level of noise. This component, that we might just as well call a solid-state relay, was selected because it is comes in the form of a package similar to a TO220, a little bigger, and equipped with four pins. The pinout will not cause confusion because the symbols shown on our diagram are engraved or printed on the packaging. Since this circuit is not yet very common, we need to mention that it’s available from the Conrad Electronics website (www1.uk.conrad.com).

For the purpose of safe operation, the circuit is protected by a GeMOV on the mains side, called Varistor, VDR or SiOV depending on the manufacturer. The model indicated here is generally available. The load will be limited to 2 A, considering the model selected for IC1, which is more than sufficient for the application planned here. Finally, since a number of components in this circuit are connected directly to the mains power supply, the assembly should be placed in a completely insulated housing for obvious safety reasons.

Author: Christian Tavernier - Copyright: Elektor Electronics Magazine

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Voice Bandwidth Filter

This circuit passes frequencies in the 300Hz - 3.1kHz range, as present in human speech. The circuit consists of cascaded high-pass and low-pass filters, which together form a complete band-pass filter. One half of a TL072 dual op amp (IC1a) together with two capacitors and two resistors make up a second-order Sallen-Key high-pass filter. With the values shown, the cut-off frequency (3dB point) is around 300Hz. As the op amp is powered from a single supply rail, two 10kO resistors and a 10µF decoupling capacitor are used to bias the input (pin 5) to one-half supply rail voltage.

The output of IC1a is fed into the second half of the op amp (IC1b), also configured as a Sallen-Key filter. However, this time a low-pass function is performed, with a cut-off frequency of about 3.1kHz. The filter component values were chosen for Butterworth response characteristics, providing maximum pass-band flatness. Overall voltage gain in the pass-band is unity (0dB), with maximum input signal level before clipping being approximately 3.5V RMS. The 560O resistor at IC1bs output provides short-circuit protection.

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Fire Alarm Using Thermistor

Small and simple unit, Can be used for Home-Security purpose

In this fire alarm circuit, a Thermistor works as the heat sensor. When temperature increases, its resistance decreases, and vice versa. At normal temperature, the resistance of the Thermistor (TH1) is approximately 10 kilo-ohms, which reduces to a few ohms as the temperature increases beyond 100 C. The circuit uses readily available components and can be easily constructed on any general-purpose PCB.

Circuit Diagram:

Fire Alarm Using Thermistor Circuit Diagram

Parts	Description
R1	470R
R2	470R
R3	33K
R4	560R
R5	470R
R6	47K
R7	2.2K
R8	470R
C1	10uF-16V
C2	0.04uF-63V
C3	0.01uF-63V
Q1	BC548
Q2	BC558
Q3	SL100B
D1	Red Led
D2	1N4001
IC1	NE555
SPKR	1W-8R
TH1	Thermistor-10K

Circuit Operation:

Timer IC NE555 (IC1) is wired as an astable multivibrator oscillating in audio frequency band. Switching transistors Q1 and Q2 drive multivibrator IC1. The output of IC1 is connected to NPN transistor Q3, which drives the loudspeaker (SPKR) to generate sound. The frequency of IC1 depends on the values of resistors R6, R7 and capacitor C2. When Thermistor TH1 becomes hot, it provides a low-resistance path to extend positive voltage to the base of transistor Q1 via diode D2 and resistor R3. Capacitor C1 charges up to the positive voltage and increases the ‘on’ time of alarm. The higher the value of capacitor C1, the higher the forward voltage applied to the base of transistor Q1. Since the collector of transistor Q1 is connected to the base of transistor Q2, transistor Q2 provides positive voltage to reset pin 4 of IC1. R5 is used such that IC1 remains inactive in the absence of positive voltage. D2 stops discharging of capacitor C1 when the Thermistor connected to the positive supply cools down and provides a high-resistance (10k) path. It also stops the conduction of Q1. To prevent the Thermistor from melting, wrap it up in mica tape. The circuit works off a 6V-12V regulated power supply. D1 is used to indicate that power to the circuit is switched on.

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Supply Voltage Indicator

A novel supply voltage monitor which uses a LED to show the status of a power supply.

This simple and slightly odd circuit can clearly show the level of the supply voltage (in a larger device): as long as the indicator has good 12 volts at its input, LED1 gives steady, uninterrupted (for the naked eye) yellow light. If the input voltage falls below 11 V, LED1 will start to blink and the blinking will just get slower and slower if the voltage drops further - giving very clear and intuitive representation of the supplys status. The blinking will stop and LED1 will finally go out at a little below 9 volts. On the other hand, if the input voltage rises to 13 V, LED2 will start to glow, getting at almost full power at 14 V. The characteristic voltages can be adjusted primarily by adjusting the values of R1 and R4. The base-emitter diode of T2 basically just stands in for a zener diode.

The emitter-collector path of T1 is inversely polarized and if the input voltage is high enough - T1 will cause oscillations and the frequency will be proportional to the input voltage. The relaxation oscillator ceases cycling when the input voltage gets so low that it no longer can cause breakdown along the emitter-collector path. Not all small NPN transistors show this kind of behavior when inversely polarized in a similar manner, but many do. BC337-40 can start oscillations at a relatively low voltage, other types generally require a volt or two more. If experimenting, be careful not to punch a hole through the device under test: they oscillate at 9-12 V or not at all.

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ECG Amplifier By TLC274

This circuit allows an ECG signal to be displayed on an oscilloscope. Opamps IC1a, b and d form an instrumentation amplifier with a gain of 201. IC1c amplifies the common-mode signal by a factor of 31, and supplies this signal to the right leg. The first consequence of this is that the body is brought to a defined common-mode level, so that the signal will not lie outside the range of the instrumentation amplifier.

The second consequence is that negative feedback is applied to the common-mode signal, so that the amplitude of this (undesired) signal is reduced even further. Diodes D1 through D4, along with resistors R1 and R5, are added to the circuit to protect the inputs against damage from excessive electrostatic charges. The CMRR (common-mode rejection ratio) of the instrumentation amplifier can be set using P1.

To make this adjustment, connect both inputs of the instrumentation amplifier together, and then connect a 100mV, 50Hz AC signal between the connected inputs and earth. Measure the output signal using an oscilloscope, and adjust P1 to minimize the level of the output signal. It is important that the electrodes make very good contact with the skin. In our test measurements, winding three uninsulated copper wires several times around the index fingers (and the right leg) proved to be sufficient to provide a good signal.

The amplitude of the ECG signal measured with this arrangement was 200mV. The current consumption of this circuit is only 2mA, so the batteries should last a long time. This circuit must never be connected to a mains-operated power supply, in consideration of safety precautions that are necessary when making this sort of measurement on the human body.

Source : www.extremecircuits.net

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Tuned Radio Frequency TRF Receiver

Superheterodyne receivers have been mass-produced since around 1924, but for reasons of cost did not become successful until the 1930s. Before the second world war other, simpler receiver technologies such as the TRF receiver and the regenerative receiver were still widespread. The circuit described here is based on the old technology, but brought up-to-date a The most important part of the circuit is the input stage, where positive feedback is used to achieve good sensitivity and selectivity. The first stage is adjusted so that it is not quite at the point of oscillation. This increases the gain and the selectivity, giving a narrow bandwidth.

To achieve this, the potentiometer connected to the drain of the FET must be adjusted very carefully: optimal performance of the receiver depends on its setting. In ideal conditions several strong stations should be obtainable during the day using a 50 cm antenna. At night, several times this number should be obtainable. The frequency range of the receiver runs from 6 MHz to 8 MHz. This range covers the 49 m and the 41 m shortwave bands in which many European stations broadcast. Not bad for such a simple circuit! The circuit employs six transistors. The first stage is a selective amplifier, followed by a transistor detector. Two low-frequency amplifier stages complete the circuit.

The final stage is a push-pull arrangement for optimal drive of the low-impedance loudspeaker. This circuit arrangement is sometimes called a ‘1V2 receiver’ (one preamplifier, one detector and two audio-frequency stages). Setting-up is straightforward. Adjust P1 until the point is reached where the circuit starts to oscillate: a whistle will be heard from the loudspeaker. Now back off the potentiometer until the whistle stops. The receiver can now be tuned to a broadcaster. Occasional further adjustment of the potentiometer may be required after the station is tuned in. The receiver operates from a supply voltage of between 5 V and 12 V and uses very little current. A 9 V PP3 (6F22) battery should give a very long life.

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Laser Alarm

This circuit is a laser alarm system like the one we see in various movies. It uses a laser pointer beam to secure your valuables and property. Essentially, when the beam gets interrupted by a person, animal or object, the resistance of a photodiode will increase and an alarm will be activated. The laser and the receiver can be fitted in same box, sharing a common power supply. As the receiver draws less than 10 mA on average, you’ll soon find that the laser is the most current hungry device! Mirrors are used to direct the beam in whatever setup you require. Examples of a passage and an area protected by the alarm are shown in the diagram.

In the circuit diagram we find a TL072 op-amp (IC1.A) configured as voltage comparator between the voltage reference provided by the adjustable voltage divider P1/R4 and the light-dependent voltage provided by the voltage divider consisting of photodiode D1 and fixed resistor R3. When the laser beam is interrupted, the voltage on comparator pin 2 drops below that at pin 3, causing the output to swing to (almost) the positive supply voltage and indicating an alarm condition. This signal can drive a siren, a computer or a light that hopefully will deter the intruder.

Alternatively it can be used to ‘silently’ trigger a more sophisticated alarm. Resistor R2 provides some hysteresis to prevent oscillation when the two comparator input voltages are almost equal. Capacitor C1 makes the circuit immune to short, accidental interruptions of the beam, e.g., by flying insects. If you want your circuit to have faster responses you can reduce its value to 1 µF. The operation of the circuit is illustrated by the waveform diagram, which also proves the hysteresis action that sets an upper and a lower threshold on the input voltage. You can also see the delay introduced by capacitor C1.

The circuit is simple and could be assembled on a piece of breadboard. After assembling the circuit and testing it, you should mount it in a black box that has just a small hole. You may decide to put the laser in the same box but only if you are sure there is no way the photodiode can ‘see’ the laser beam directly. The small hole should be filled with a black drinking straw so that only light from the direction of the laser beam can enter. With the appropriate setup of the box and the mirrors, the laser beam is so intense that even direct sunlight cannot affect the operation of the photodiode.

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1W LED Driver Circuit

This circuit is designed to drive the 1W LEDs that are now commonly available. Their non-linear voltage to current relationship and variation in forward voltage with temperature necessitates the use of a 350mA, constant-current power source as provided by this supply. In many respects, the circuit operates like a conventional step-down (buck) switching regulator.

Transistor Q1 is the switching element, while inductor L1, diode D1 and the 100mF capacitor at the output form the energy transfer and storage elements. The pass transistor (Q1) is switch-ed by Q2, which together with the components in its base circuit, forms a simple oscillator. A 1nF capacitor provides the positive feedback necessary for oscillation. The output current is sensed by transistor Q3 and the two parallelled resistors in its base-emitter circuit.

Circuit diagram:

1W LED Driver Circuit Diagram

When the current reaches about 350mA, the voltage drop across the resistors exceeds the base-emitter forward voltage of transistor Q3 (about 0.6V), switching it on. Q3’s collector then pulls Q2’s base towards ground, switching it off, which in turn switches off the main pass transistor (Q1).

The time constant of the 15kW resistor and 4.7nF capacitor connected to Q2’s base adds hysteresis to the loop, thus ensuring regulation of the set output current. The inductor was made from a small toroid salvaged from an old computer power supply and rewound with 75 turns of 0.25mm enamelled copper wire, giving an inductance of about 620mH. The output current level should be trimmed before connecting your 1W LED. To do this, wire a 10W 5W resistor across the output as a load and adjust the value of one or both of the resistors in the base-emitter circuit of Q3 to get 3.5V (maximum) across the load resistor.

Author: Nick Baroni - Copyright: Silicon Chip

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Fuse Box 1991 BMW 325i Diagram

Fuse Box 1991 BMW 325i Diagram - Here are new post for Fuse Box 1991 BMW 325i Diagram.

Fuse Box 1991 BMW 325i Diagram

Fuse Panel Layout Diagram Parts: Headlights, High beam indicator, Headlights, Auxiliary fan, Lights/Turn hazard warning, Active check control, Glove box light, Electro-mechanical convertible top, Wiper/washer, Stop lights/cruise control, Active check control, Antilock braking system, Cruise control, Map reading light, Rear defogger, Injection electronics, Ignition key warning/seatbelt warning, back-up lights, Tachometer/Fuel economy gauges, Injection electronics, Brake warning system, Cruise control, Injection electronics, adio, speedometer, on-board computer, Headlights, Heated seats, Power windows, Auxiliary fan, Interior Lights, Power mirrors, Heater/Air conditioning, Auxiliary fan.

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Fuse BOx BMW Z3 Underdash 1996 Diagram

Fuse BOx BMW Z3 Underdash 1996 Diagram - Here are new post for Fuse BOx BMW Z3 Underdash 1996 Diagram.

Fuse BOx BMW Z3 Underdash 1996 Diagram

Fuse Panel Layout Diagram Parts: ABS system, motorsport, airbag, air conditioning, automatic transmission, anti theft sytem, cigar lighter, clock, connector for optional, cruise control, cruise seats adjustment, electronic immobilizer, exhausy gas diagnosis, fuel pump, headlight cleaning system, heated seat window, heated blower, brake light, parking light, reversing light, side ligth, low beam headlight, interior light, high beam headlight.

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Cell Phone RF Radiation Detector LED

From rookieelectronics: This is my favorite project, its too simple and very interesting because it does not require any voltage source. it converts RF frequency waves from cell phone (whenever you call or send a text) to little current to flash a LED.

Actually this project is also called as LED power meter, it is used to test RF equipments. It can detect output power of our FM transmitters, by simply connecting voltmeter in the place of the load(LED) of this circuit.

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Use Of Alignment Tools and Dial Indicators Zurn Coupling

Use Of Alignment Tools and Dial Indicators Zurn Coupling

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LTC3605A – 20V 5A Synchronous Step Down Regulator

The LTC®3605A is a high efficiency, monolithic synchronous buck regulator using a phase lockable controlled on-time constant frequency, current mode architecture. PolyPhase operation allows multiple LTC3605A regulators to run out of phase while using minimal input and output capacitance. The operating supply voltage range is from 20V down to 4V, making it suitable for dual, triple or quadruple lithium-ion battery inputs as well as point of load power supply applications from a 12V or 5V rail.

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Simple Water Activated Alarm

The circuit uses a 555 timer wired as an astable oscillator and powered by the emitter current of the BC109C. Under dry conditions, the transistor will have no bias current and be fully off. As the probes get wet, a small current flows between base and emitter and the transistor switches on. A larger current flows in the collector circuit enabling the 555 osillator to sound.

Simple Water Activated Alarm  Circuit diagram :

An On/Off switch is provided and remember to use a non-reactive metal for the probe contacts. Gold or silver plated contacts from an old relay may be used, however a cheap alternative is to wire alternate copper strips from a piece of veroboard. These will eventually oxidize over but as very little current is flowing in the base circuit, the higher impedance caused by oxidization is not important. No base resistor is necessary as the transistor is in emitter follower, current limit being the impedance at the emitter (the oscillator circuit).

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2500W Phase Control

This circuit controls resistive and inductive loads up to 2,500W. Its main functional device is an integrated phase control circuit - Siemens TLE3103. It contains its own power supply, a zero voltage crossing detector circuit and a logic driver. An additional feature is the low voltage input to enable/disable triac firing enabling/disabling the logic driver. The function is as follows: pin13 TLE3103 open (floating), trigger output active, tied to ground trigger output disabled.

2500W Phase Control  Circuit diagram

An UP and a DOWN button control a 32-step digital potentiometer (IC2, AD5228) via the debouncer IC1 (MAX6817). The potentiometer has a power on reset pin which might be tied to ground causing the potentiometer to start at midscale, or to VCC causing it to start at zero scale. The desired function is selectable using jumper JP1. The triac (capable of driving 40A loads) is a bit overkill for the desired power but the BTA41 has an isolated body and therefore handling of the board under voltage is less dangerous as it is with phase on the package. The circuit uses a 68μH inductance, but this might be replaced with a 100 resistor, then replacing the inductance C5 should have a value of 47nF.

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10 Amp Solar Charge Controller

The SCC2 is a solar charge controller, its function is to regulate the power flowing from a photovoltaic panel into a rechargeable battery. It features easy setup with one potentiometer for the float voltage adjustment, an equalize function for periodic overcharging, and automatic temperature compensation for better charging over a range of temperatures.

10 Amp Solar Charge Controller  Circuit Diagram with Parts List

The goal of the circuit design was to make a charge controller with analog simplicity, high efficiency, and reliability. A medium power solar system can be built with a 12V solar panel up to 10 amps, the SCC2, and a rechargeable battery. The SCC2 works with lead acid, NiCD and NiMH batteries with ratings from less than one to several hundred amp-hours. With the appropriate parts selection, the SCC2 can be operated at 6V, 12V, 24V or other voltages.

Specifications:

• Maximum solar panel current: 10 Amps
• Night time battery drain current: approximately 1ma
• Nominal battery voltage: 6V, 12V or 24V.
• See the full SCC2 specifications for more information.

Theory:
The SCC2 acts as a medium power DC current switch between the + terminals of the PV and battery. Diode D1 prevents reverse night time current flow from the battery back to the PV panel.

When the PV voltage is high enough to charge the battery, zener diode D2 conducts and turns on transistor Q2. Q2 switches the power for the rest of the circuit on. The circuit is switched off at night. IC2 provides a 5 volt regulated voltage to power the comparator circuits, it also provides a reference voltage for comparator IC1a.

When the battery voltage is below the desired full voltage and needs charging, comparator IC1a turns on and activates Q1 and Q3, this allows the solar charging current to flow into the battery. Note that Q3 is a P-channel mosfet, this allows the circuit to be wired with a common ground for the solar panel and battery. The solar current loop is drawn in heavy lines on the schematic.

When the battery reaches the full charge point, IC1a operates as a comparator based schmidt trigger oscillator, it switches the solar current off and on. The switching causes the battery voltage to oscillate a few tens of millivolts above and below the desired set point. A rail-to-rail op-amp is required for proper operation, 741 style op-amps will not work in this circuit.

The red/green charging/full LED is driven between the output of IC1a and IC1b. IC1b has an inverted version of the IC1a signal. Pin 5 of IC1b only needs an approximate center point to work as an on-off comparator, it is connected to the varying IC1a pin 2 so that it does not require another reference divider circuit.

The resistors and thermistor on the input side of IC1a form a resistive bridge circuit that is used to compare the battery voltage to a reference voltage coming from IC2/R8/R9. The potentiometer adjusts the voltage point around which the circuit will oscillate on full charge. Resistor R7 adds positive feedback to IC1a for a schmidt trigger characteristic and C6 sets the maximum frequency of oscillation. The thermistor provides thermal compensation, as the temperature goes down, the float voltage setting goes up.

The equalize switch, S1a, forces the circuit on for intentional overcharging. Switch S1b and R1 can be used to select a different float voltage range, you can experiment with this by using different values of R1, typically R1 should be greater than 1M.

Alignment:

• Start with a charged battery, connect the solar panel directly to the battery until the battery voltage is at or above the desired full setting, this also that the panel is capable of charging the battery.
• While measuring the battery voltage, adjust VR1 clockwise to align the float voltage set point.  If the LED turns red before it reaches the desired float voltage, the battery will need to charge for a while.
• When the battery is fully charged, it should be at the float voltage and the led should show alternating colors.
• The float voltage should be set when the board and battery are at room temperature. Typical 12V set points are 13.8V for a gell cell and 14.5V for a wet cell.  For 6V, divide those by two, for 24V, multiply by 2.
• Follow your battery manufacturers recommendations for the best settings.
• Readjust the float voltage after the battery has reached a full charge.
• The float voltage should be set when the circuit is at room temperature.

Use:
Connect the solar panel to the SCC2 solar panel input connectors, connect the battery to the SCC2 output connectors. Put the solar panel in the sun, and watch the battery charge up. Systems where the battery is frequently discharged way down should occasionally be run in equalize mode for a few hours or a full day. It is best to monitor the battery voltage during this operation, disable equalization if the battery voltage goes above 16V (12V version).

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3W FM Transmitter Circuit

Description

This is the schematic for an FM transmitter with 3 to 3.5 W output power that can be used between 90 and 110 MHz. Although the stability isnt so bad, a PLL can be used on this circuit.

This is a circuit that Ive build a few years ago for a friend, who used it in combination with the BLY88 amplifier to obtain 20 W output power. From the notes that I made at the original schematic, it worked fine with a SWR of 1 : 1.05 (quite normal at my place with my antenna).

 Circuit Diagram

 Parts:
R1,R4,R14,R15 10K 1/4W Resistor
R2,R3 22K 1/4W Resistor
R5,R13 3.9K 1/4W Resistor
R6,R11 680 Ohm 1/4W Resistor
R7 150 Ohm 1/4W Resistor
R8,R12 100 Ohm 1/4W Resistor
R9 68 Ohm 1/4W Resistor
R10 6.8K 1/4W Resistor
C1 4.7pF Ceramic Disc Capacitor
C2,C3,C4,C5,C7,C11,C12 100nF Ceramic Disc Capacitor
C6,C9,C10 10nF Ceramic Disc Capacitor
C8,C14 60pF Trimmer Capacitor
C13 82pF Ceramic Disc Capacitor
C15 27pF Ceramic Disc Capacitor
C16 22pF Ceramic Disc Capacitor
C17 10uF 25V Electrolytic Capacitor
C18 33pF Ceramic Disc Capacitor
C19 18pF Ceramic Disc Capacitor
C20 12pF Ceramic Disc Capacitor
C21,C22,C23,C24 40pF Trimmer Capacitor
C25 5pF Ceramic Disc Capacitor
L1 5 WDG, Dia 6 mm, 1 mm CuAg, Space 1 mm
L2,L3,L5,L7,L9 6-hole Ferroxcube Wide band HF Choke (5 WDG)
L4,L6,L8 1.5 WDG, Dia 6 mm, 1 mm CuAg, Space 1 mm
L10 8 WDG, Dia 5 mm, 1 mm CuAg, Space 1 mm
D1 BB405 or BB102 or equal (most varicaps with C = 2-20 pF [approx.] will do)
Q1 2N3866
Q2,Q4 2N2219A
Q3 BF115
Q5 2N3553
U1 7810 Regulator
MIC Electret Microphone
MISC PC Board, Wire For Antenna, Heatsinks

Notes:
1. Email Rae XL Tkacik with questions, comments, etc.
2. The circuit has been tested on a normal RF-testing breadboard (with one side copper). Make some connections between the two sides. Build the transmitter in a RF-proof casing, use good connectors and cable, make a shielding between the different stages, and be aware of all the other RF rules of building.
3. Q1 and Q5 should be cooled with a heat sink. The case-pin of Q4 should be grounded.
4. C24 is for the frequency adjustment. The other trimmers must be adjusted to maximum output power with minimum SWR and input current.
5. Local laws in some states, provinces or countries may prohibit the operation of this transmitter. Check with the local authorities.

 Author: Rae XL Tkacik
e-mail: vocko@atlas.cz
Source: http://www.aaroncake.net/circuits/index.asp

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