nº822

Prototype of sensitive mains voltage detector.

nº821

The frequency of the led ring oscillator can be controlled by shortening the loop on the odd stages.

nº820

Simple light activated JT.

nº819

Simple set-up for checking SMPS PWM controller FSD200.

nº818

Simple sound controlled lamp.

nº817

Simple growing bar with 30 yellow leds, supply 12V.

nº816

Histerese com par diferencial: pontos notáveis.

nº815

Analog lock system with 3 potmeters.
Code set: 243
1) Choose code configuration in the dial panel.
2) Code panel: press correspondent tact-switch while R-trimmer is adjusted until set led is turned off.
3) Repeat step 2 for 2nd and 3rd digits. After 3rd digit is adjusted unlock green led turns on.
4) Unsettle potmeters. System is locked.
Note: knowing 2 digits unlocks the system.

nº814

Mains supplied load controlled by 1 tact-switch with total galvanic isolation.

nº813

Simple flip-flop for mains supplied load is controlled by tact-switches having galvanic isolation and no external power supply on the low voltage side.

nº812

Sound effect "Code accepted or invalid code", supply 2xNiMH.

nº811

Quick setup for converting TDT signal back to analog TV signal (UHF channel 68) to be used with old TV receivers having RF input but no scart input.

Configuração experimental para conversão do sinal TDT para sinal analógico, UHF canal 68, para receptores TV antigos com entrada RF e sem entrada scart.

nº810

Simple twin-T oscillator with 1 bipolar transistor directly driving yellow led, supply 2xNiMH.

nº809

Slow "knight rider" sequence with 2 transistors, supply 9V.

nº808

JT directly driving increasing/decreasing led bar.

nº807

Bilateral led bar controlled by 1 transistor RC oscillator, supply 9V.

nº806

Bargraph with 10 Bi-color red-green leds, supply 9V.

nº805

Led growing bar with 1 SCR, supply 12V.

nº804

Sensitive mains voltage detector with 1 low gain bipolar transistor, supply 9V.

nº803

Blinking white led with emitter follower configuration, supply 9V.

nº802

Emitter follower RC sinewave oscillator, supply 9V.
Oscilador sinusoidal RC com transístor na configuração seguidor de emissor(cc), alimentação 9V.

nº801

Mains voltage voltmeter with 14 leds starting at 220Vac.

nº800

Wire self-inductance transforms an RLC JT into a practical RC JT.

nº799

Simple bidirectional led loop, supply 9V.

nº798

Random flasher with 9 leds, supply 230Vac/50Hz.

nº797

Aplicação do modelo híbrido simplificado ao oscilador de deslocamento de fase com ajuste da capacidade intermédia.

nº796

Simple SCR latch operated by single tact-switch, supply 230Vac/50Hz.

nº795

Remote led latch using mains installation.
Comando ON/OFF para led através da rede de tomadas.

nº794

Multipoint led opto latch, supply 4xNiMH.

nº793

Simple latch with 1 transistor operated by a single tact-switch, supply 2xNiMH.

nº792

Two Colpitts oscillators beating at the same frequency make a sensitive metal detector. Two adjustments: sensitivity and audio volume. Supply 2xNiMH.
Detector de metais por batimento de dois osciladores Colpitts. Dois ajustes: sensibilidade e volume. Alimentação 2xNiMH.

nº791

Blinking a white led with RLC "Joules Thief".
Pisca-pisca com led branco baseado no "Ladrão de Joules" RLC.

nº790

Non-volatile opto latch, supply 230Vac/50Hz.

nº789

Minimalist free energy led flasher with 2 bipolar transistors. Flashes every 12 seconds approximately.

nº788

Basic "Joules Thief" with coupled inductors drives white led and operates intermittently.

nº787

Growing bar with 14 white leds based on bargraph circuit, supply 2xNiMH.

nº786

Light controlled bargraph with 1 transistor, supply 9V.

nº785

Simple led chaser, supply 2xNiMH.

nº784

RLC "Joules Thief" with violet led.

nº783

Mains supplied bargraph with 10 white leds.

nº782

Simple bargraph with 1 transistor, supply 24V.

nº781

Capacitive power supply with symmetrical output voltages.
Output +5Vdc (current 0 to 70mAdc)
Output -5Vdc (current 0 to 70mAdc)
Regulators input voltage with open load = 35Vdc.
The current through the simulated bipolar capacitors should be kept balanced.

nº780

Simple RLC JT: the resistor is not in the path of the inductor.

nº779

Very simple bargraph with 12 leds; 1 limiter resistor, supply 24V.

nº778

Sound effect "Firework", supply 9V.
Efeito sonoro "Fogo de artifício", alimentação 9V.

nº777

Simple SCR bargraph with 5 stages; each stage drives a 50W bulb; supply 230Vac/50Hz.

nº776

Led flasher running at 1,2V/300nA.(average)

nº775

Free energy led beacon.
Flashes de led amarelo auto-alimentados.