Schematic Diagram

Best it mean UJT battry charger schema diagram. This UJT battry charger schema diagram will not work unless the battery to  be charged is connected with proper polarity. The  battery voltage controls the charger and when the  battery is fully charged, the charger will not supply  current to the battery. The battery charging the  current is obtained through the SCR when it is triggered  into the conducting state by the UJT relaxation  oscillator. 

The oscillator is only activated when the battery voltage is low. V8281 of the UJT is derived from the voltage of the battery to be charged, and since Vp= Vn= V8281 ; the higher V828` the higher Vp. When Vp exceeds the breakdown voltage of the zener diode Zl, the UJT will cease to fire and the SCR will not conduct. This indicates that the battery has attained its desired charge as set by R2.

UJT battry charger diagram diagrams