Circuits – 7 Mhz 5 Watts CW Transmitter
The above 7 Mhz 5 Watts CW transmitter circuit was found in one of back issues of sprat. Still i am wondering how 5 watts juiced out from this tiny crystal oscillator circuit.
Category «Circuits»
Circuit – FM Bandstop Filter for RTL SDR
FM Bandstop Filter for RTL SDR The given FM band stop filter is nothing more than a simple Band stop filter for the frequency range of 88-108Mhz. FM Broadcast transmitters transmit at high power and can cause overloading and intermodulation problems on simple receivers like RTL-SDR due to its wide open front end. The said …
Circuits – Simple zener diode tester
Simple zener diode tester Circuit – FM Bandstop Filter for RTL SDR
Circuits – 7MHz CW / AM QRP Transmitter
7MHz CW / AM QRP Transmitter – D.Prabakaran The circuit of a 7MHz C W / A M QRP transmitter described here can be used to transmit either CW or audio frequency modulated signal over a 7MHz carrier. The carrier frequency oscillator is crystal controlled using 7MHz crystal in its fundamental mode. The tank circuit …
Circuits – Offset tuning indicator for CW
An NE567 tone decoder, tuned to the transceiver`s CW offset frequency, ensures that the transceiver will be transmitting on the same frequency as the received CW signal. Simply tune the transceiver so that the LED lights. Eight to 13 Vdc is required; this can be taken from the transceiver supply or an extra battery. Audio …
Circuits – Simple tester checks LCDs
Manufacturers of electronic equipment use LCDs for calculators, watches, mini-videogames, and pagers, for example. In comparison with LED-based displays,which consume power on the order of tens of milliwatts, an LCD consumes onlya few microwatts. The LCD thus saves power by a factor of approximately 1000. Checking an LED is as simple as checking a semiconductor …
Circuits – White LED Torch
This low-cost circuit is suitable for powering flashlights, emergency lighting and other applications in which it is desirable to power white LEDs from one or two primary cell batteries. The transistor, lk resistor [Rll and the tapped inductor form a blocking oscillator. When the power button is pressed, the transistor …
Circuits – DARK ROOM TIMER
The timer circuit described here provides a pleasant musical tone in your darkroom at 1-second intervals.The circuit takes up very little space and can be easily converted into a metronome. Unijunction transistor (UJT) T1 functioning as a relaxation oscillator triggers the phase-shift audio oscillator circuit built around transistor T2, turning it on and off. As …
Circuits – Short Wave Transmitter
This transmitter circuit operates in shortwave HF band (6 MHz to15 MHz), and can be used for shortrange communication and for educational purposes. The circuit consists of a mic amplifier, a variable frequency oscillator, and modulation amplifier stages. Transistor T1 (BF195) is used as a simple RF oscillator. Resistors R6 and R7 determine base bias, …
Circuits – Check Digital Or Linear Circuits With The Flick Of A Switch
A simple logic probe in concert with a signal source can be used to check digital as well as linear circuits. With the flick of a switch, the probe can inject a test signal or check the logic state of a digital signal. Comprising just one CMOS IC (CD4011B) and a handful of components, the …