nº943

Simple bargraph with dual red-green leds, supply 24V

nº942

The emitter coupled astable multivibrator

nº941

Overlap of two led sequences with 5 dual red-green leds, supply 12V

nº940

Minimalist reflex radio receiver for MW band; only ferrite antenna, no earth connection, no variable capacitor; tuning by variable inductor; 2 bipolar transistors; loudspeaker output, supply 1xNiMH

nº939

Mains power failure alarm with 2 transistors; stand-by current drawn from LR03 battery is less than 100uA

nº938

Simple SCR random led sequencer with 5 white leds, supply 24V

nº937

Knight rider led effect with 20 leds, 1 BC transistor, supply 24V

nº936

8 leds, 1 bipolar transistor, supply 9V

nº935

Simple led chaser with progressive shortening, supply 2xNiMH

nº934

Simple QC2.0 - 12V mode tester for USB charger. Checks if USB charger is true QC2.0

nº933

Precise refrigerator temperature alarm. When internal temperature exceeds preset value between 0 and 10 degrees Celsius a powerfull alarm signal is triggered. It can be heard even with door closed. Low current consumption in stand-by, Supply 4xNiMH

nº932

Simple "red led catch game" with adjustable speed, supply 2xNiMH

nº931

SW band to MW band frequency converter with 1 transistor, supply 4xNiMH.

nº930

Ganged variable capacitor with reading scale

nº929

Simple lamp flasher controlled by LDR, supply +5V_USB

nº928

Four levels clapper for incandescent lamp; low sensitivity to speech, high sensitivity to clapping, supply 230Vac/50Hz.

nº927

Dimmer for incandescent lamp with 4 levels: OFF, L_min, L_med, L_max; tact-switch operates with total galvanic isolation, supply 230Vac/50Hz.

nº926

Staircase lamp controlled by smartphone ringtone. The ringtone audio signal derived from earphones output activates staircase lamp for the predefined timing. Complete galvanic isolation between TRS plug and circuit hot side is achieved by: 1) using one optocoupler to trigger monostable circuit and 2) A photovoltaic led coupler consisting on the hot side white led voltage regulator coupled to yellow led which supplies energy to the optocoupler audio trigger amplifier.

nº925

Light controlled audio spectral glider, supply 3V

nº924

Audio effect "wah wah", suppy 3V