video buffer/repeater

This universal video amplifier is intended as a buffer/repeater in a long coaxial cable to keep the signal at a reasonable level. Its gain is about 6 dB. The circuit is built from readily available components: some tran- sistors and a few others. The circuit consists of a two-stage amplifier, T1and T2, and an emitter follower that functions as impedance converter. The bandwidth at —3 dB is not less than 20 MHz. Current con- sumption at a suplly voltage of 12 V amounts to about 20 mA. The power supply needs to be regulated to pre- vent lines and other noise on the screen. The buffer/repeater is very suitable for 12 V video buffer/repeater 1150 W/150 being combined with the video selec- for featured elsewhere in this issue. The present circuit, with R1omitted, is then used as a buffer for the output of the inverter. Its input impedance is then around 4 1(52. R20R1 1 T2 C13V BC Iar C457BC. R6 2V4) R5 88 g Eaal