world electronics - Experimental transmissions

Flashes a LED when detecting an incoming call
Powered by one 1.5V cell

Parts:
R1 100K 1/4W Resistor
R2 3K9 1/4W Resistor
R3 1M 1/4W Resistor
C1,C2 100nF 63V Polyester Capacitors
C3 220µF 25V Electrolytic Capacitor
D1 LED Red 10mm. Ultra-bright (see Notes)
D2 1N5819 40V 1A Schottky-barrier Diode (see Notes)
Q1 BC547 45V 100mA NPN Transistor
IC1 7555 or TS555CN CMos Timer IC
L1 Sensor coil (see Notes)
B1 1.5V Battery (AA or AAA cell etc.)

Circuit diagram

This little circuit can be used to dim lights up to about 350 watts. It uses a simple, standard TRIAC circuit that, in my expirience, generates very little heat. Please note that this circuit cannot be used with fluorescent lights.

Circuit diagram

The circuit for a powerful AM transmitter using ceramic resonator/filter of 3.587 MHz is presented here. This circuit is based on transistor for the core operation of the circuit. Resonators/filters of other frequencies such as 5.5 MHz, 7 MHz and 10.7 MHz may also be used. Use of different frequency filters/resonators will involve corresponding variation in the value of inductor used in the tank circuit of oscillator connected at the collector of transistor T1. This is the figure of the circuit;