Easy to build high-quality PLL FM transmitter with typical output power of 5 W and no-tune design. The transmitter includes RDS/SCA input and Audio/MPX input with optional pre-emphasis. It can be used with or without stereo encoder. Tuning over the FM band is provided by two buttons that control dual-speed PLL.
Click here to download the full size of the above Circuit.
The transmitter can work also without the LCD display. Some experience with building devices of this kind are highly recommended. Supply voltage 11-13. 8 V (stabilized or from a battery) Supply current up to 1. 2 A Standard frequency range 87. 5-107. 9 MHz Audio/MPX input sensitivity 2 V pp (for 75 kHz freq. deviation)RDS/SCA input sensitivity 0. 2 V pp (for 7. 5 kHz freq. deviation) Board dimensions 109 x 54 mm Q1 - BF240 Q2 - BFG135 (BFG235) Q3 - 2SC1971 (2N3553) + heatsink Q4 - BC547B D1 - SB260 (1N5822, 1N581x) D2, D3 - BBY40 (BBY31) D4 - LED 5mm U1 - 78L09 U2 - TSA5511 (TSA5512, SDA3202) in DIL socket U3 - PIC16F627A in DIL socket (programmed) U4 - 78L05 R1, R2, R11, R17, R20 - 10k R3, R21 - 270R R4, R15 - 33k R5, R7, R12, R13, R16 - 680R R6, R14 - 18k R8 - 47R (33R if Q2 is BFG235) R9 - 18R R10 - 4k7 R18 - 3k3 R19 - 100k smd 1206 R22 - 91R R23 - trimmer 5k mini C1, C4, C9, C12, C13, C14, C15, C30, C31, C32, C33, C35 - 10n smd 1206 (C) C2, C17, C20 - 15p (C) C3 - 10p (C) (15p if the PCB is single-sided) C5 - 1n (C) C6, C28, C29, C34 - 100u/10V (E) C7, C26 - 10u/35V (E) C8 - 22p (C) C10 - 47p (C) (33p if Q3 is 2N3553) C11, C27 - 100n (C) C16, C36 - 33p (C) C18 - cap. trimmer 50p C19 - 470u/16V (E) C21 - 4u7/50V (E) C22 - 330p (C) C23, C24 - 47p (C) C25 - 3n3 (P) L1 - 3. 5 turns on 7 mm diameter L2 - 1uH/815mA choke, or about 10 turns of thin wire on mini ferrite core L3 - 2. 5 turns on 6 mm diameter (4. 5 turns if Q3...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
characters left: