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 transistors and a few others. The circuit consists of a two-stage amplifier, T1 and T2, and an emitter follower that functions as impedance converter. The bandwidth at -3 dB is not less than 20 MHz. Current consumption at a supply voltage of 12 V amounts to
about 20 rnA. The power supply needs to be regulated to prevent lines and other noise on the screen. The buffer/repeater is very suitable for being combined with the video selector featured elsewhere in this issue. The present circuit, with R1 omitted, is then used as a buffer for the output of the inverter. Its input impedance is then around 4 k
about 20 rnA. The power supply needs to be regulated to prevent lines and other noise on the screen. The buffer/repeater is very suitable for being combined with the video selector featured elsewhere in this issue. The present circuit, with R1 omitted, is then used as a buffer for the output of the inverter. Its input impedance is then around 4 k
1 comments:
Interesting. Can't we remove T2 and configure T1 to provide the whole gain alone ? 6 dB ≡ 2 times the voltage, so possible.
A.Genchev.
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