This low power fm transmitter is designed to use an input from another sound source and transmits on the commercial FM band. This low power fm radio transmitter it is actually quite powerful. The first stage is the oscillator, and is tuned with the variable capacitor. Select an unused frequency, and carefully adjust C3 until the background noise is removed.

Here's a portable FM broadcast radio receiver for reception of FM broadcast band based around FET transistor. The topology is a classic grounded-gate FET VHF Hartley oscillator. The drain resonator inductance is centre-tapped with feedback to the source through a small capacitance. By tapping down towards the cold-end of the coil the feedback isn't as critical as your usual source-drain capacitor feedback and it tends to be far less difficult to get to work across a broad range of frequencies. The RFC to an RC source circuit to implement self-quenching is very traditional for super-regenerative detectors. The quench gets frequency-modulated somewhat by the drain current, so it varies with signal strength and the recovered modulation, this is typical for self-quenched circuits.

This article shows you how to build a very simple FM transmitter from thirteen components, a Printed Circuit Board (PCB) and a 9v battery. This project was designed to be mounted on a PCB, however you don’t have to. You could construct the project on Vero board (strip board) or any other 0.1” pitch style of project board. If you just want to experiment with this circuit, you don’t even need a board; you can just solder the component s together and let the completed project just rest on the work top. No matter which style you choose, try to keep all component leads nice and short. You could also make the PCB much smaller than the one shown here which is approx. 3 cm square. This is a good size to keep the unit small but nicer to work on for beginners. If you wanted to make one really small, you could use all SMT parts.

Park Assist circuit was designed as an aid in parking the car near the garage wall when backing up. LED D7 illuminates when bumper-wall distance is about 20 cm., D7+D6 illuminate at about 10 cm. and D7+D6+D5 at about 6 cm. In this manner you are alerted when approaching too close to the wall. All distances mentioned before can vary, depending on infra-red transmitting and receiving LEDs used and are mostly affected by the color of the reflecting surface. Black surfaces lower greatly the device sensitivity. Obviously, you can use this circuit in other applications like liquids level detection, proximity devices etc.

ESR Meter is an irreplaceable tool for troubleshooting and repairing electronic equipment by determining performance and health of electrolytic capacitors. Unlike other ESR Meters that only measure ESR value this one measures capacitor's ESR value as well as its capacitance all at the same time. Additionally, ESR Meter also tests and identifies PINs of all transistors such as Bipolar (NPN, PNP), FETs, MOSFETs (N-Channel, P-Channel, enhancement-mode and depletion-mode MOSFETs), Thyristors, SCRs and Triacs. Tests and identifies PINs and voltage of diodes, dual diodes, varicap diodes (and their capacity), zener diodes (test voltage up to 5V) and LEDs. It measures resistance of resistors, power resistors, coils starting from just 0.1Ω up to 20MΩ.

Circuit-Zone.com © 2013. All Rights Reserved.