Multivibrador astável simples para duas frequências com temporização definida pelos mesmos componentes

Very simple multivibrator that runs at two different frequencies with the same components. It depends if Rb is connected to Vcc or to the ground.

Comparação entre o oscilador Colpitts e o oscilador C-L-C em "T" para transístor bipolar

Flip-flop simples de 2 leds para altifalante piezoeléctrico, alimentação 2xNiMH

Simple two led flip-flop for piezoelectric speaker, supply 2xNiMH.

Gerador de sinal de alarme com 1 transístor e led pisca-pisca branco alimentado a 1,5V

Simple LC regenerative oscillator with one bipolar transistor. The HF frequency is detected by the BE junction driving the transistor to the cut-off point again and again. This is the LF audio signal. An extra RC network hicks this low frequency. Tank circuit resonation and battery impedance allow to turn-on a white led with 1,5V supply voltage.

Interruptor on/off óptico para led branco, por radiação IV, alimentação 1xNiMH

Optical on/off switch for white led by infrared radiation finger reflection. Supply 1xNiMH.

Flashes de led violeta alimentados por pilha de 1,5V

Simple two transistor multivibrator drives violet led flashes with one LR6 battery.

Oscilador de bloqueio por luz com led violeta, alimentação 3xNiMH

Light blocking oscillator with violet led, supply 3xNiMH.